List of U.S. county name etymologies (J–M)

This is a list of U.S. county name etymologies, covering the letters J to M.

J

• Jack County, Texas: named for Patrick Churchill Jack and his brother William Houston Jack, both soldiers of the Texas Revolution
• Jackson County, Alabama: President Andrew Jackson
• Jackson County, Arkansas: President Andrew Jackson
• Jackson County, Colorado: Jackson County is named for United States President Andrew Jackson.
• Jackson County, Florida: President Andrew Jackson
• Jackson County, Georgia: Congressman, Senator and Governor James Jackson.
• Jackson County, Illinois: is named after Andrew Jackson who had just defeated the British in the Battle of New Orleans, and who later became U.S. President.
• Jackson County, Indiana: Jackson is named for United States President Andrew Jackson.
• Jackson County, Iowa: President Andrew Jackson
• Jackson County, Kansas: President Andrew Jackson
• Jackson County, Kentucky: President Andrew Jackson
• Jackson County, Michigan: Named for United States President Andrew Jackson.
• Jackson County, Minnesota: President Andrew Jackson
• Jackson County, Mississippi: President Andrew Jackson
• Jackson County, Missouri: President Andrew Jackson
• Jackson County, North Carolina: President Andrew Jackson
• Jackson County, Ohio: President Andrew Jackson
• Jackson County, Oklahoma: President Andrew Jackson
• Jackson County, Oregon: President Andrew Jackson
• Jackson County, South Dakota: named for Dakota territorial legislator J. R. Jackson
• Jackson County, Tennessee: President Andrew Jackson
• Jackson County, Texas: President Andrew Jackson
• Jackson County, West Virginia: President Andrew Jackson
• Jackson County, Wisconsin: President Andrew Jackson
• Jackson Parish, Louisiana: President Andrew Jackson
• James City County, Virginia: named by King Charles of England, presumably for King James
• Jasper County, Georgia: William Jasper
• Jasper County, Illinois: is named after William Jasper.
• Jasper County, Indiana: Jasper is named for Sgt. William Jasper, a famous scout for the Continentals during the Revolutionary War.
• Jasper County, Iowa: William Jasper
• Jasper County, Mississippi: William Jasper
• Jasper County, Missouri: William Jasper
• Jasper County, South Carolina: William Jasper
• Jasper County, Texas: William Jasper
• Jay County, Indiana: Jay is named for U.S. Secretary of State John Jay.
• Jeff Davis County, Georgia — Both this county and its counterpart in Texas are named for Jefferson Davis, the only President of the Confederacy.
• Jeff Davis County, Texas
• Jefferson County, Alabama: President Thomas Jefferson
• Jefferson County, Arkansas: President Thomas Jefferson
• Jefferson County, Colorado: Jefferson County is named for the extralegal Jefferson Territory, of which it was a part of from 1859 to 1861.
• Jefferson County, Florida: President Thomas Jefferson
• Jefferson County, Georgia: President Thomas Jefferson
• Jefferson County, Idaho: President Thomas Jefferson
• Jefferson County, Illinois: Jefferson is named for United States President Thomas Jefferson.
• Jefferson County, Indiana: Jefferson is named for United States President Thomas Jefferson.
• Jefferson County, Iowa: President Thomas Jefferson
• Jefferson County, Kansas: President Thomas Jefferson
• Jefferson County, Kentucky: Named for Thomas Jefferson, who was governor of Virginia at the time.
• Jefferson County, Mississippi: President Thomas Jefferson
• Jefferson County, Missouri: President Thomas Jefferson
• Jefferson County, Montana: President Thomas Jefferson
• Jefferson County, Nebraska: President Thomas Jefferson
• Jefferson County, New York: President Thomas Jefferson
• Jefferson County, Ohio: President Thomas Jefferson
• Jefferson County, Oklahoma: President Thomas Jefferson
• Jefferson County, Oregon: President Thomas Jefferson
• Jefferson County, Pennsylvania: President Thomas Jefferson
• Jefferson County, Tennessee: President Thomas Jefferson
• Jefferson County, Texas: President Thomas Jefferson
• Jefferson County, Washington: President Thomas Jefferson
• Jefferson County, West Virginia: President Thomas Jefferson
• Jefferson County, Wisconsin: President Thomas Jefferson
• Jefferson Parish, Louisiana: President Thomas Jefferson
• Jefferson Davis County, Mississippi — Both this county and the Louisiana parish of the same name are also named for Jefferson Davis.
• Jefferson Davis Parish, Louisiana
• Jenkins County, Georgia: named for Georgia Governor Charles Jones Jenkins
• Jennings County, Indiana: Jennings is named for Governor of Indiana Jonathan Jennings.
• Jerauld County, South Dakota: for H. A. Jerauld, a member of the Dakota territorial council.
• Jerome County, Idaho: Unknown. Presumably, one of three early settler whose first name was Jerome.
• Jersey County, Illinois: Jersey is named for the US state New Jersey.
• Jessamine County, Kentucky: named for Jessamine Creek, an alternate spelling of Jasmine, a flowering plant.
• Jewell County, Kansas: for Col. Lewis R. Jewell, of the Sixth Kansas Cavalry Regiment.
• Jim Hogg County, Texas: Jim Hogg was the 21st Governor of Texas.
• Jim Wells County, Texas: James Babbage Wells, Jr. was a judge and Democratic boss in South Texas.
• Jo Daviess County, Illinois: Jo Daviess County is named after Joseph Hamilton Daveiss, a soldier killed at the Battle of Tippecanoe.
• Johnson County, Arkansas: named for Ben Johnson, a Territorial Judge.
• Johnson County, Georgia: named for Georgia governor, senator, and unsuccessful U.S. vice-presidential candidate Herschel Vespasian Johnson.
• Johnson County, Illinois: named for Richard Mentor Johnson, who was then a U.S. Congressman from Kentucky.
• Johnson County, Indiana: Johnson is named for John Johnson, a judge of the Indiana Supreme Court.
• Johnson County, Iowa: named for Vice President Richard Mentor Johnson
• Johnson County, Kansas: Johnson is named for Thomas Johnson, a nineteenth-century Methodist missionary to the Shawnee tribe.
• Johnson County, Kentucky: named for Vice President Richard Mentor Johnson
• Johnson County, Missouri: named for Vice President Richard Mentor Johnson
• Johnson County, Nebraska: named for Vice President Richard Mentor Johnson
• Johnson County, Tennessee: Named in honor of Thomas Johnson, early settler.
• Johnson County, Texas: named for Middleton Johnson, a Texas Ranger, soldier, and politician.
• Johnson County, Wyoming: re-named (1879) for E.P. Johnson, a Cheyenne attorney.
• Johnston County, North Carolina: named for Gabriel Johnston, Governor of North Carolina
• Johnston County, Oklahoma: for Douglas H. Johnston, governor of the Chickasaw Nation
• Jones County, Georgia: for U. S. Representative James Jones.
• Jones County, Iowa: George Wallace Jones, one of Iowa's first United States Senators.
• Jones County, Mississippi: named for John Paul Jones, well-known naval fighter in the American Revolutionary War.
• Jones County, North Carolina: named for Willie Jones, a Revolutionary leader and president of the North Carolina Council of Safety
• Jones County, South Dakota: named for Iowa Senator George Wallace Jones
• Jones County, Texas: Jones County is named for Anson Jones, the last president of the Republic of Texas. Its county seat is Anson.
• Josephine County, Oregon: for a creek, probably named after Virginia Josephine Rollins Ort.
• Juab County, Utah: Ute Indian word meaning "valley or plain".
• Judith Basin County, Montana: named by explorer William Clark, for his future wife Julia "Judith" Hancock
• Juneau County, Wisconsin: for Solomon Juneau, an early French trader and first major of Milwaukee
• Juneau City and Borough, Alaska: for Joe Juneau, a gold prospector
• Juniata County, Pennsylvania: from Iroquoian word 'Onayutta', meaning "Standing Stone".

K

• Kalamazoo County, Michigan: Named for the river that runs through it, the Native American form of which was probably "Ke-Ken-a-ma-zoo," which means "boiling water."
• Kalawao County, Hawaii
• Kalkaska County, Michigan: Created by Henry Schoolcraft. Schoolcraft's family name formerly was Calcraft. The Ks may have been added to make the name appear more like a Native American word.
• Kanabec County, Minnesota: named after the Ojibwe "Ginebig", meaning "Snake," after the Snake River
• Kanawha County, West Virginia: from the Native American term, kanawha, meaning "place of white stone"
• Kandiyohi County, Minnesota: the Dakota name for several lakes, meaning "where the buffalo fish come".
• Kane County, Illinois: Kane is named after U.S. senator Elias Kane.
• Kane County, Utah: after Thomas L. Kane, an influential supporter of the Mormons
• Kankakee County, Illinois: from the Miami Indian word "teeyaahkiki", meaning: "Open country"
• Karnes County, Texas: named for Henry Karnes, a soldier in the Texas Revolution.
• Kauai County, Hawaii — Named after its largest island, Kauaʻi.
• Kaufman County, Texas: named for David Spangler Kaufman, a diplomat and U.S. congressman from Texas
• Kay County, Oklahoma: Originally designated as "County K", before names were assigned.
• Kearney County, Nebraska: named for Fort Kearny (sic) and misspelled, in honor of General Stephen Watts Kearny..
• Kearny County, Kansas: Stephen Watts Kearny
• Keith County, Nebraska: Named for M. C. Keith, a rancher
• Kemper County, Mississippi: named for Reuben Kemper, an early settler who rebelled against Spanish rule.
• Kenai Peninsula Borough, Alaska
• Kendall County, Illinois: Kendall County is named after Amos Kendall, who was the editor of the Frankfort, Kentucky newspaper, and went on to be an important advisor to President Andrew Jackson.
• Kendall County, Texas: named for George Wilkins Kendall, a journalist and Mexican-American War correspondent.
• Kenedy County, Texas: named for Mifflin Kenedy, an early rancher in the area.
• Kennebec County, Maine: from the Eastern Abenaki /kínipekʷ/, meaning "large body of still water"
• Kenosha County, Wisconsin: from Chippewa, meaning "pickerel", a large fish.
• Kent County, Delaware: named for Kent, an English County.
• Kent County, Maryland: named for Kent, an English County.
• Kent County, Michigan: Named for James Kent, a jurist who represented Michigan Territory in its dispute with Ohio over the Toledo Strip.
• Kent County, Rhode Island: named for Kent, an English County.
• Kent County, Texas: named for Andrew Kent, who died at the Battle of the Alamo.
• Kenton County, Kentucky — Named after frontiersman Simon Kenton.
• Keokuk County, Iowa: for Keokuk, chief of the Sauk tribe.
• Kern County, California: named for Edward Kern, cartographer for General John C. Fremont's expedition
• Kerr County, Texas: for James Kerr, a congressman of the Republic of Texas.
• Kershaw County, South Carolina: for state legislator Joseph B. Kershaw
• Ketchikan Gateway Borough, Alaska
• Kewaunee County, Wisconsin: for disputed Chippewa language terms that might have meant "prairie hen" or "I cross a point of land by boat."
• Keweenaw County, Michigan: Named after the Native American word "Kee-wi-wai-non-ing", which means "portage" or "place where portage is made."
• Keya Paha County, Nebraska: for Dakota language words Ké-ya Pa-há Wa-kpá, which, translated, mean "turtle hill river"
• Kidder County, North Dakota: named for Jefferson Parrish Kidder, who served as a delegate to the United States Congress from Dakota Territory
• Kimball County, Nebraska: for Thomas L. Kimball, an official of the Union Pacific Railroad
• Kimble County, Texas: George C. Kimble, who died at the Battle of the Alamo.
• King County, Texas — Named for William Philip King, who died at the Alamo.
• King County, Washington — Named for William Rufus King, but was 'renamed' in honor of Dr. Martin Luther King, Jr. in 2005 .
• King George County, Virginia: Named in honor of King George I of Great Britain
• King William County, Virginia: Named in honor of King William III of England
• King and Queen County, Virginia: Named in honor of King William III of England and Queen Mary II of England
• Kingfisher County, Oklahoma possibly for a local rancher named King Fisher, and given additional currency in association with the belted kingfisher bird
• Kingman County, Kansas: in honor of Samuel A. Kingman, who was then Chief Justice of Kansas.
• Kings County, California: from the Kings River, originally named Rio de los Santos Reyes (River of the Holy Kings).
• Kings County, New York: Named in honor of King Charles II of England.
• Kingsbury County, South Dakota: named for two brothers, George W. and T. A. Kingsbury, who were members of several Territorial Legislatures.
• Kinney County, Texas: named for Henry Lawrence Kinney, an early settler.
• Kiowa County, Colorado: named for the Kiowa Native American tribe.
• Kiowa County, Kansas: named for the Kiowa Native American tribe.
• Kiowa County, Oklahoma: named for the Kiowa Native American tribe.
• Kit Carson County, Colorado: Kit Carson County is named for explorer, trapper, and "Wild West" figure Kit Carson.
• Kitsap County, Washington: named for Chief Kitsap, of the Suquamish tribe
• Kittitas County, Washington: A Native American word of uncertain meaning or origin
• Kittson County, Minnesota: named after Canadian fur trader and railroad entrepreneur Norman Kittson.
• Klamath County, Oregon: for the Native american Klamath people
• Kleberg County, Texas: named for [Robert J. Kleberg], an early settler.
• Klickitat County, Washington: The native Klickitat people of the Yakama Nation.
• Knott County, Kentucky: named for James Proctor Knott, Governor of Kentucky
• Knox County, Illinois: All Knox Counties in the United States are named after Revolutionary War General Henry Knox, who became the first United States Secretary of War.
• Knox County, Indiana: Henry Knox
• Knox County, Kentucky: Henry Knox
• Knox County, Maine: Henry Knox
• Knox County, Missouri: Henry Knox
• Knox County, Nebraska: Henry Knox
• Knox County, Ohio: Henry Knox
• Knox County, Tennessee: Henry Knox
• Knox County, Texas: Henry Knox
• Kodiak Island Borough, Alaska
• Koochiching County, Minnesota: A native America term (Ojibwe or Cree) meaning "at the place of inlets",
• Kootenai County, Idaho: for the Native American Kootenay tribe
• Kosciusko County, Indiana: Kosciusko is named for Tadeusz Kościuszko, a Polish ally of the Americans during the Revolutionary War.
• Kossuth County, Iowa: named after Lajos Kossuth, Regent-President of Hungary who went to exile to America
• Kusilvak Census Area, Alaska: named for the Kusilvak Mountains

L

• La Crosse County, Wisconsin: Early explorer Zebulon Pike saw the Indians playing a game similar to Lacrosse, a French game called such because the rackets resembled a bishop's crozier.
• La Moure County, North Dakota: named for Judson LaMoure of who served many terms in the Dakota and North Dakota legislatures
• La Paz County, Arizona: The Spanish word for "Peace" was the name of a ghost town in the newly formed county
• La Plata County, Colorado: La Plata County is named for the La Plata Mountains, which were named by Spanish explorers Silvestre Vélez de Escalante and Francisco Atanasio Domínguez during their 1776 expedition through Colorado. (The mountains were named for their reputed silver ore; La Plata is Spanish for "silver").
• La Porte County, Indiana: LaPorte means the door or the port in the French language.
• LaSalle County, Illinois: named for the early French explorer René-Robert Cavelier, Sieur de La Salle.
• La Salle County, Texas: René-Robert Cavelier, Sieur de La Salle
• La Salle Parish, Louisiana: René-Robert Cavelier, Sieur de La Salle
• Labette County, Kansas: possibly for a Pierre Labette who lived near the mouth of the stream of the same name.
• Lac qui Parle County, Minnesota: French: "Lake that speaks"
• Lackawanna County, Pennsylvania: Native American Lenape word for "stream that forks"
• Laclede County, Missouri: named after Pierre Laclède, founder of St. Louis, Missouri.
• Lafayette County, Arkansas: All Lafayette Counties in the United States, as well as Lafayette Parish in Louisiana, are named for Gilbert du Motier, marquis de Lafayette (1757–1834), a French general who played a major role in the Revolutionary War.
• Lafayette County, Florida
• Lafayette County, Mississippi
• Lafayette County, Missouri
• Lafayette County, Wisconsin
• Lafayette Parish, Louisiana
• Lafourche Parish, Louisiana
• Lagrange County, Indiana: Lagrange is named after the Marquis de la Fayette's home outside of Paris, France.
• Lake County, California: For the dominance of Clear Lake
• Lake County, Colorado: Lake County is named for Twin Lakes, two lakes (now a reservoir) located just south of Leadville.
• Lake County, Florida: Named for the large number of lakes the county contains.
• Lake County, Illinois: Named for its location on Lake Michigan
• Lake County, Indiana: Lake is named for its location on Lake Michigan.
• Lake County, Michigan: Named for the several small lakes that are found in the county.
• Lake County, Minnesota: Named for its location on Lake Superior
• Lake County, Montana: Named for the dominance of Flathead Lake
• Lake County, Ohio: Lake is named for its location on Lake Erie.
• Lake County, Oregon: Named for the numerous large lakes within the county
• Lake County, South Dakota: Named for the numerous lakes within the county
• Lake County, Tennessee: From Reelfoot Lake, the county's most significant geographic feature along with the Mississippi River.
• Lake and Peninsula Borough, Alaska
• Lake of the Woods County, Minnesota: Named for the large Lake of the Woods in the forested land of the area
• Lamar County, Alabama: Lucius Quintus Cincinnatus Lamar II (1825 1893), a US Senator, Secretary of the Interior, and Supreme Court justice.
• Lamar County, Georgia: Lucius Quintus Cincinnatus Lamar II
• Lamar County, Mississippi: Lucius Quintus Cincinnatus Lamar II
• Lamar County, Texas: named for Mirabeau Buonaparte Lamar, the second president of Texas and the uncle of L. Q. C. Lamar II (above).
• Lamb County, Texas: named for George A. Lamb, who died in the Battle of San Jacinto.
• Lamoille County, Vermont: Undocumented. Possibly a misspelling of the intended name of Lake Champlain, or for the French la Moelle ("the marrow").
• Lampasas County, Texas: Undocumented. Named for the Lampasas River, possibly after the old Lampazos mission in Mexico, or the Spanish name for any of several plants in the vicinity.
• Lancaster County, Nebraska: Named after the cities of Lancaster, Pennsylvania and Lancaster, England.
• Lancaster County, Pennsylvania: For Lancashire, England
• Lancaster County, South Carolina: For Lancaster, Pennsylvania
• Lancaster County, Virginia: For Lancaster, Pennsylvania
• Lander County, Nevada: Named for Frederick W. Lander; chief engineer of a federal wagon route through the area
• Lane County, Kansas: named after James H. Lane who was a leader of the Jayhawker abolitionist movement and served as one of the first U.S. Senators from Kansas
• Lane County, Oregon: named in honor of Joseph Lane, Oregon's first territorial governor.
• Langlade County, Wisconsin: for Charles Langlade,a fur merchant and one of the first settlers in Wisconsin
• Lanier County, Georgia: named after the Georgia poet Sidney Lanier.
• Lapeer County, Michigan: Named from the French "la pierre," meaning flint or flint stone.
• Laramie County, Wyoming: named for Jacques La Ramee, a French-Canadian fur-trader
• Larimer County, Colorado: Larimer County is named for "General" William Larimer, Jr., the founder of Denver, Colorado.
• LaRue County, Kentucky: named after John LaRue, an early settler in this area
• Las Animas County, Colorado: Las Animas County is named for the Purgatoire River, which was once known as the Río de las Animas Perdidas en Purgatorio, Spanish for "River of Souls Lost in Purgatory."
• Lassen County, California: named after Peter Lassen, was one of General John C. Fremont's guides,
• Latah County, Idaho: the name is Nez Perce and means "the place of pine trees and pestle"
• Latimer County, Oklahoma: Named for J. S. Latimer, member of the Oklahoma Constitutional Convention.
• Lauderdale County, Alabama: named for Col. James Lauderdale, who died during the first Battle of New Orleans
• Lauderdale County, Mississippi: named for Col. James Lauderdale
• Lauderdale County, Tennessee: named for Col. James Lauderdale
• Laurel County, Kentucky: Named for the mountain laurel trees common in the area.
• Laurens County, Georgia: named for Colonel John Laurens, a soldier and statesman during the American Revolutionary War.
• Laurens County, South Carolina: named for Henry Laurens, president of the Continental Congress
• Lavaca County, Texas: for the Lavaca River, originally called "Les Veches" by early French explorers, for the wild buffalo grazing on its banks. Later translated to Spanish "La Vaca", meaning "the cattle"
• Lawrence County, Alabama: named after James Lawrence, a captain in the United States Navy
• Lawrence County, Arkansas: after Capt. James Lawrence
• Lawrence County, Illinois: after Capt. James Lawrence
• Lawrence County, Indiana: after Capt. James Lawrence
• Lawrence County, Kentucky: after Capt. James Lawrence
• Lawrence County, Mississippi: after Capt. James Lawrence
• Lawrence County, Missouri: after Capt. James Lawrence
• Lawrence County, Ohio: after Capt. James Lawrence
• Lawrence County, Pennsylvania: named after the USS Lawrence, Oliver Hazard Perry's original flagship at the Battle of Lake Erie during the War of 1812.
• Lawrence County, South Dakota: named for "Colonel" John Lawrence who came to the county as first treasurer. after serving in the Dakota Territorial Legislature
• Lawrence County, Tennessee: after Capt. James Lawrence
• Le Flore County, Oklahoma: named for a prominent local family of Choctaw/French descent
• Le Sueur County, Minnesota: named for the French explorer Pierre-Charles Le Sueur
• Lea County, New Mexico: for U. S. Army Capt. Joseph Calloway Lea, founder of the New Mexico Military Academy
• Leake County, Mississippi: named for Walter Leake, the Governor of Mississippi
• Leavenworth County, Kansas: after Colonel Henry Leavenworth, who established the original Fort Leavenworth
• Lebanon County, Pennsylvania: a Biblical name meaning "White Mountain."
• Lee County, Alabama: named after Confederate General Robert E. Lee
• Lee County, Arkansas: Gen. Robert E. Lee
• Lee County, Florida: Gen. Robert E. Lee
• Lee County, Georgia: named for Richard Henry Lee (the father of Robert E. Leewho had proposed in the Continental Congress that the colonies declare themselves free and independent.
• Lee County, Illinois: Richard Henry Lee
• Lee County, Iowa: Gen. Robert E. Lee, probably named for probably William Elliot Lee, a land dealer who owned an area of Iowa that included the future county.
• Lee County, Kentucky: Uncertain. Either Robert E. Lee or Gen. Lighthorse Harry Lee, Revolutionary War officer; Virginia governor.
• Lee County, Mississippi: Gen. Robert E. Lee
• Lee County, North Carolina: Gen. Robert E. Lee
• Lee County, South Carolina: Gen. Robert E. Lee
• Lee County, Texas: Gen. Robert E. Lee
• Lee County, Virginia: Gen. Lighthorse Harry Lee,
• Leelanau County, Michigan: Created by Henry Schoolcraft, who gave the name "Leelinau" to some Native American women in his stories.
• Leflore County, Mississippi; named for Choctaw leader Greenwood LeFlore.
• Lehigh County, Pennsylvania: derived from the Delaware Indian term Lechauweki or Lechauwekink, meaning "where there are forks"
• Lemhi County, Idaho: named for King Limhi, a figure in the Book of Mormon.
• Lenawee County, Michigan: Created from a Native American word meaning "man," either from the Delaware "leno or lenno" or the Shawnee "lenawai."
• Lenoir County, North Carolina: named for William Lenoir (1751–1839), an officer in the American Revolutionary War
• Leon County, Florida: named after the Spanish explorer Juan Ponce de León.
• Leon County, Texas: in honor of Martín De León, the founder of Victoria, Texas.
• Leslie County, Kentucky: named for Preston H. Leslie, Governor of Kentucky
• Letcher County, Kentucky: named for Robert P. Letcher, Governor of Kentucky
• Levy County, Florida: named for David Levy Yulee, industrialist and US Senator
• Lewis County, Idaho: named for Meriwether Lewis a co-leader of the Lewis and Clark Expedition.
• Lewis County, Kentucky: Meriwether Lewis
• Lewis County, Missouri: Meriwether Lewis
• Lewis County, New York: in honor of Morgan Lewis, governor of New York
• Lewis County, Tennessee: Meriwether Lewis
• Lewis County, Washington: Meriwether Lewis
• Lewis County, West Virginia: For Colonel Charles Lewis, soldier and pioneer leader
• Lewis and Clark County, Montana: for Meriwether Lewis and William Clark, who undertook the first espedition across the United States to the Pacific Coast.
• City of Lexington, Virginia
• Lexington County, South Carolina: for the Battle of Lexington from the American Revolutionary War.
• Liberty County, Florida: named for the philosophical ideal
• Liberty County, Georgia: honors Lyman Hall and Button Gwinnett of Georgia's f signers of the Declaration of Independence.
• Liberty County, Montana: named for the philosophical ideal
• Liberty County, Texas: named for the philosophical ideal following World War I
• Licking County, Ohio: named for the [[Licking River {Ohio}|Licking River]], whose etymology is highly conjectural.
• Limestone County, Alabama: from the name of the creek that flows over limestone bedrock
• Limestone County, Texas: from numerous limestone deposits in the area
• Lincoln County, Arkansas: Named for Abraham Lincoln, the 16th president of the United States
• Lincoln County, Colorado: Abraham Lincoln
• Lincoln County, Georgia: named for Benjamin Lincoln a leading general in the American Revolutionary War.

• Lincoln County, Idaho: Abraham Lincoln
• Lincoln County, Kansas: Abraham Lincoln
• Lincoln County, Kentucky: Benjamin Lincoln
• Lincoln County, Maine: after the city of Lincoln, England
• Lincoln County, Minnesota: Abraham Lincoln
• Lincoln County, Mississippi: Abraham Lincoln
• Lincoln County, Missouri: Benjamin Lincoln
• Lincoln County, Montana: Abraham Lincoln
• Lincoln County, Nebraska: Abraham Lincoln
• Lincoln County, Nevada: Abraham Lincoln
• Lincoln County, New Mexico: for President Abraham Lincoln
• Lincoln County, North Carolina: Benjamin Lincoln,
• Lincoln County, Oklahoma: Abraham Lincoln
• Lincoln County, Oregon: Abraham Lincoln
• Lincoln County, South Dakota: After Lincoln County, Maine
• Lincoln County, Tennessee: Benjamin Lincoln
• Lincoln County, Washington: Abraham Lincoln
• Lincoln County, West Virginia: Abraham Lincoln
• Lincoln County, Wisconsin: Abraham Lincoln
• Lincoln County, Wyoming: Abraham Lincoln
• Lincoln Parish, Louisiana: Abraham Lincoln
• Linn County, Iowa: named for Senator Lewis Linn of Missouri
• Linn County, Kansas: named for Senator Lewis Linn of Missouri
• Linn County, Missouri: named for Senator Lewis Linn of Missouri
• Linn County, Oregon: named for Senator Lewis Linn of Missouri
• Lipscomb County, Texas: named for Judge Abner Smith Lipscomb, a secretary of state of the Republic of Texas
• Litchfield County, Connecticut: named for City of Lichfield, England
• Little River County, Arkansas: named for a river that formed the county boundary
• Live Oak County, Texas: the Texas live oak tree under which the petition for a new county was signed
• Livingston County, Illinois: named after Edward Livingston mayor of New York City , Congressman, and Secretary of State

• Livingston County, Kentucky: Named for Edward Livingston
• Livingston County, Michigan: Named for Edward Livingston.
• Livingston County, Missouri: Named for Edward Livingston
• Livingston County, New York: in honor of Robert R. Livingston, a delegate to the 1775 Continental Congress
• Livingston Parish, Louisiana: Named for Edward Livingston
• Llano County, Texas
• Logan County, Arkansas
• Logan County, Colorado: Logan County is named for Civil War general and Vice-Presidential candidate John A. Logan, who died two months before the county's formation.
• Logan County, Illinois: named for Dr. John Logan, pioneer physician and father of Gen. John A. Logan.
• Logan County, Kansas: named for General John A. Logan.
• Logan County, Kentucky: Gen. Benjamin Logan. advocate for Kentucky's statehood in the Virginia legislature.
• Logan County, Nebraska: named for General John A. Logan.
• Logan County, North Dakota: named for General John A. Logan.
• Logan County, Ohio: Gen. Benjamin Logan. advocate for Kentucky's statehood in the Virginia legislature.
• Logan County, Oklahoma: named for General John A. Logan.
• Logan County, West Virginia: For Logan, famous Indian chief of the Mingo tribe
• Long County, Georgia: named for Dr. Crawford W. Long, the Georgia's pioneer anesthesiologist
• Lonoke County, Arkansas: for a "lone oak" tree landmark
• Lorain County, Ohio: Lorain County was named after the province of Lorraine, France
• Los Alamos County, New Mexico: named after Los Alamos Ranch School via Los Alamos National Laboratory. Los Alamos is Spanish for "the Cottonwoods".
• Los Angeles County, California: "the angels". Originally Pueblo del Río de Nuestra Señora la Reina de Los Ángeles de Porciuncula (the Town of the River of Our Lady, Queen of the Angels).
• Loudon County, Tennessee: after Fort Loudon, named for John Campbell, 4th Earl of Loudoun.
• Loudoun County, Virginia: for John Campbell, 4th Earl of Loudoun.
• Louisa County, Iowa: Louisa Massey, an Iowa townswoman who avenged the murder of her brother
• Louisa County, Virginia: Princess Louise of Great Britain, the youngest surviving daughter of George II of Great Britain
• Loup County, Nebraska: after the Loup River, from the French for "wolf"
• Love County, Oklahoma: Overton Love, a member of a Chickasaw family
• Loving County, Texas: named for Oliver Loving, a cattle rancher and pioneer of the cattle drive
• Lowndes County, Alabama: named for statesman William Jones Lowndes.
• Lowndes County, Georgia: William Jones Lowndes.
• Lowndes County, Mississippi: William Jones Lowndes.
• Lubbock County, Texas: Thomas Saltus Lubbock, a Texas Ranger and Confederate Civil War soldier
• Lucas County, Iowa: named for Robert Lucas, governor of the Iowa Territory and of Ohio.
• Lucas County, Ohio: Robert Lucas
• Luce County, Michigan: Named for Cyrus G. Luce, former governor of Michigan.
• Lumpkin County, Georgia: named for Wilson Lumpkin, a Congressman and governor of Georgia.
• Luna County, New Mexico: for Solomon Luna, rancher and political figure
• Lunenburg County, Virginia: named for the former Germsn Duchy of Brunswick-Lüneburg
• Luzerne County, Pennsylvania: Named for the Chevalier de la Luzerne, French minister to the United States
• Lycoming County, Pennsylvania: derived from a Delaware Indian word meaning "sandy or gravelly creek."
• Lyman County, South Dakota: named for territorial legislator W.P. Lyman
• City of Lynchburg, Virginia: Named for John Lynch, who founded the first European settlement at the site.
• Lynn County, Texas: named for William Lynn, a soldier believed to have died defending the Alamo
• Lyon County, Iowa: ia named for Nathaniel Lyon, the first United States general killed in the Civil War.
• Lyon County, Kansas: Nathaniel Lyon
• Lyon County, Kentucky: Nathaniel Lyon
• Lyon County, Minnesota: Nathaniel Lyon
• Lyon County, Nevada: Nathaniel Lyon

M

• Mackinac County, Michigan: Named from the French interpretation of a Native American word that meant "great turtle," the shape of nearby Mackinac Island from a distance.
• Macomb County, Michigan: Named for Alexander Macomb.
• Macon County, Alabama: for General Nathaniel Macon, a North Carolina statesman and president pro tempore of the US Senate.
• Macon County, Georgia: Nathaniel Macon
• Macon County, Illinois: Nathaniel Macon
• Macon County, Missouri: Nathaniel Macon
• Macon County, North Carolina: Nathaniel Macon
• Macon County, Tennessee: Nathaniel Macon
• Macoupin County, Illinois: the Miami-Illinois term for the American lotus
• Madera County, California: the Spanish word for "wood", as lumbering was a major industry in the county at the time.
• Madison County, Alabama: Madison is named for fourth U.S. President James Madison.
• Madison County, Arkansas: James Madison
• Madison County, Florida: James Madison
• Madison County, Georgia: James Madison
• Madison County, Idaho: James Madison
• Madison County, Illinois: James Madison
• Madison County, Indiana:: James Madison
• Madison County, Iowa: James Madison
• Madison County, Kentucky: James Madison
• Madison County, Mississippi: James Madison
• Madison County, Missouri: James Madison
• Madison County, Montana: for the Madison River, after James Madison
• Madison County, Nebraska: for the capital of Wisconsin, the oribin of most early settlers to the county, after James Madison
• Madison County, New York: James Madison
• Madison County, North Carolina: James Madison
• Madison County, Ohio: James Madison
• Madison County, Tennessee: James Madison
• Madison County, Texas: James Madison
• Madison County, Virginia: James Madison
• Madison Parish, Louisiana: James Madison
• Magoffin County, Kentucky:named for Beriah Magoffin, a Kentucky governor
• Mahaska County, Iowa: named for Chief Mahaska, of the Iowa tribe.
• Mahnomen County, Minnesota: the Ojibwe word for wild rice.
• Mahoning County, Ohio: “Mahoning” is an Indian word meaning “salt licks.”
• Major County, Oklahoma: Named for John C. Major, a delegate to the Oklahoma Constitutional Convention.
• Malheur County, Oregon: after the Malheur River that flowed through the area. French for "unfortunate river."
• City of Manassas, Virginia
• City of Manassas Park, Virginia
• Manatee County, Florida: for the manatee, an aquatic mammal of the Florida coast.
• Manistee County, Michigan: Named for the river. Derived from a Native American word which means "river at whose mouth there are islands."
• Manitowoc County, Wisconsin:An Indian word for "place of spirits"
• Marathon County, Wisconsin: for Marathon. the battlefield of ancient Greece
• Marengo County, Alabama: Named in honor of the Napoleonic-era Battle of Marengo.
• Maricopa County, Arizona: Named after the Maricopa Native American people of the region.
• Maries County, Missouri: probably a corruption of the French word "marais", meaning "marsh"
• Marin County, California: Disputed. named for Chief Marin, of the Licatiut tribe. Or for the bay called Bahia de Nuestra Senora del Rosario la Marinera
• Marinette County, Wisconsin: a corrupted form of Marie Antoinette, whose nickname Marinette was applied to Marguerite Chevalier, after whom the original town was actually named

• Marion County, Alabama — All Marion Counties in the United States are named either directly or indirectly for Francis Marion, the "Swamp Fox" of the American Revolutionary War.
• Marion County, Arkansas: Francis Marion
• Marion County, Florida: Francis Marion
• Marion County, Georgia: Francis Marion
• Marion County, Illinois: Francis Marion
• Marion County, Indiana: Francis Marion
• Marion County, Iowa: Francis Marion
• Marion County, Kansas — Named directly for Marion County, Ohio.
• Marion County, Kentucky: Francis Marion
• Marion County, Mississippi: Francis Marion
• Marion County, Missouri: Francis Marion
• Marion County, Ohio: Francis Marion
• Marion County, Oregon: Francis Marion
• Marion County, South Carolina: Francis Marion
• Marion County, Tennessee: Francis Marion
• Marion County, Texas: Francis Marion
• Marion County, West Virginia: Francis Marion
• Mariposa County, California: Spanish for Butterfly, as Spanish explorers encountered large clusters of butterflies where they named Mariposa Creek.
• Marlboro County, South Carolina: named after John Churchill, 1st Duke of Marlborough.
• Marquette County, Michigan: named for French Jesuit missionary Pere Jacques Marquette.
• Marquette County, Wisconsin: Jacques Marquette.
• Marshall County, Alabama: Named after Chief Justice John Marshall.
• Marshall County, IllinoisJohn Marshall
• Marshall County, Indiana: Marshall is named for U.S. Chief Justice John Marshall.
• Marshall County, Iowa: John Marshall
• Marshall County, Kansas: After General Francis J. Marshall, who established a ferry there and was a member of the fist legislature.
• Marshall County, Kentucky: John Marshall
• Marshall County, Minnesota: named for William Rainey Marshall, governor of Minnesota
• Marshall County, Mississippi: John Marshall
• Marshall County, Oklahoma: For the maiden name of the mother of George A. Henshaw, delegate to the Oklahoma Constitutional Convention.
• Marshall County, South Dakota: named forcounty resident Marshall Vincent.
• Marshall County, Tennessee: John Marshall
• Marshall County, West Virginia: John Marshall
• Martin County, Florida — Named for John W. Martin, Governor of Florida from 1925 to 1929.
• Martin County, Indiana — Named for Maj. John T. Martin of Kentucky.
• Martin County, Kentucky — Named for John Preston Martin, a Kentucky politician and one-term Congressman.
• Martin County, Minnesota: either for Henry Martin, a prominent land owner, or for Morgan Lewis Martin, a delegate to Congress from Wisconsin who introduced a bill for the organization of the Minnesota Territory
• Martin County, North Carolina — Named for Josiah Martin, the last colonial governor of North Carolina.
• Martin County, Texas — Named for Wylie Martin, an early settler in the region.
• City of Martinsville, Virginia — Named for the city's founder Joseph Martin, a general in the Virginia militia during the Revolutionary War.
• Mason County, Illinois: for Mason County, Kentucky
• Mason County, Kentucky: for George Mason, a Founding Father largely responsible for the Bill of Rights
• Mason County, Michigan: Named for Stevens T. Mason, former governor of Michigan.
• Mason County, Texas: after Fort Mason, named for Lieut. George Thomson Mason,killed during the Mexican–American War
• Mason County, Washington: for C. H. Mason, the first secretary of the Washington Territory.
• Mason County, West Virginia: for George Mason
• Massac County, Illinois: named for Claude Louis d'Espinchal, marquis de Massiac, the French Naval Minister.
• Matagorda County, Texas: Spanish for "thick reeds", for the canebrakes that once lined the Gulf of Mexico coastline

• Matanuska-Susitna Borough, Alaska
• Mathews County, Virginia: named for Virginia state legislator Thomas Mathews.
• Maui County, Hawaii — Named after Maui, the largest and most populous of the five islands that make up the county.
• Maury County, Tennessee: named for Abram Poindexter Maury, Sr.. pioneer, farmer, state senator.
• Maverick County, Texas: Samuel Augustus Maverick, who refused to brand his cattle. The word maverick derives from his stubborn independence
• Mayes County, Oklahoma: named for a prominent family and two chiefs in the Cherokee Nation
• McClain County, Oklahoma: Named for Charles McClain, member of the Constitutional Convention.
• McCone County, Montana: George McCone, a Montana state senator
• McCook County, South Dakota: named for Edwin McCook, military officer and Dakota Territory secretary

• McCormick County, South Carolina: named for Cyrus McCormick, inventor of the mechanical reaper.
• McCracken County, Kentucky: named for Virgil McCracken, hero in the War of 1812.
• McCreary County, Kentucky: named for James B. McCreary, Kentucky senator, representative, and governor.
• McCulloch County, Texas: named for Benjamin McCulloch, Texas Ranger and Confederate general
• McCurtain County, Oklahoma: Named for three brothers who were eacj principal chiefs of the Choctaw Nation.
• McDonald County, Missouri: Named for Alexander McDonald, Revolutionary War soldier.
• McDonough County, Illinois: Commodore Thomas Macdonough (sic), defeated the British on Lake Champlain in 1814.
• McDowell County, North Carolina: in honor of Colonel Joseph McDowell, Jr., an officer of the Revolution.
• McDowell County, West Virginia: named for James McDowell, Governor of Virginia
• McDuffie County, Georgia: named for George McDuffie, who was born in Georgia and served as a governor of and a senator from South Carolina.
• McHenry County, Illinois: named for Gen. William McHenry, who fought in the War of 1812 and the Black Hawk War
• McHenry County, North Dakota: namedfor James McHenry, an early settler
• McIntosh County, Georgia: named for the McIntosh clan who pioneered the area.
• McIntosh County, North Dakota: named for Edward H. McIntosh, a member of the legislature
• McIntosh County, Oklahoma: namedfor a family prominent in the Creek Nation,
• McKean County, Pennsylvania: Named for Governor Thomas McKean.
• McKenzie County, North Dakota: Named for Alexander McKenzie, a powerful political leaders
• McKinley County, New Mexico: for President William McKinley
• McLean County, Illinois: John McLean, first representative in Congress from Illinois and US Senator
• McLean County, Kentucky: Judge Alney McLean, officer in the War of 1812
• McLean County, North Dakota: named for John A. McLean, a prominent citizen and the first mayor of Bismarck, North Dakota.
• McLennan County, Texas: named for Neil McLennan, an early settler
• McLeod County, Minnesota: Named for Martin McLeod, pioneer fur trader, member of the council in the territorial legislature
• McMinn County, Tennessee: Named in honor of Joseph McMinn, speaker of the state senate and governor of Tennessee
• McMullen County, Texas: John McMullen, an Irish founder of a colony in Texas
• McNairy County, Tennessee: Named in honor of John McNairy Constitutional Convention delegate, US district judge for Tennessee
• McPherson County, Kansas: named for Major-General James Birdseye McPherson who was killed in Civil War
• McPherson County, Nebraska: James Birdseye McPherson
• McPherson County, South Dakota: James Birdseye McPherson
• Meade County, Kansas: Named in honor of Major-General George C. Meade
• Meade County, Kentucky: Capt. James Meade, hero in the War of 1812
• Meade County, South Dakota: named for George C. Meade
• Meagher County, Montana: named for Thomas Francis Meagher, acting Governor of the Montana Territory
• Mecklenburg County, North Carolina: Named after the German state of Mecklenburg-Strelitz. Could also be named for Charlotte of Mecklenburg, queen consort of George III of the United Kingdom.
• Mecklenburg County, Virginia: named for Charlotte of Mecklenburg
• Mecosta County, Michigan: Named for Potawatomi chief Mecosta.
• Medina County, Ohio: The county was named for the Arabian city of Medina, the former home of the Islamic faith’s prophet Mohammed.
• Medina County, Texas: the Medina River. Named after Pedro Medina, a Spanish engineer,
• Meeker County, Minnesota: Named for Bradley B. Meeker, hurist and member of the territorial legislature
• Meigs County, Ohio, is named for Return J. Meigs, Jr., the 4th Governor of Ohio and 8th Postmaster General.
• Meigs County, Tennessee, is named for Return J. Meigs, Sr., an officer in the Continental Army.
• Mellette County, South Dakota: named for Arthur C. Mellette, the first governor of South Dakota and the last governor of Dakota Territory.
• Menard County, Illinois: named for Pierre Menard, first Lieutenant Governor of Illinois.
• Menard County, Texas: Michel Branamour Menard, the founder of Galveston, Texas
• Mendocino County, California: Attributive form of the Spanish surname Mendoza, for either Antonio de Mendoza, Viceroy of New Spain, or Lorenzo Suarez de Mendoza, another Viceroy, After Cape Mendocino
• Menifee County, Kentucky: misspelled for Richard Hickman Menefee (sic), US congressman.
• Menominee County, Michigan: Named for the Menominee, who lived in the vicinity. "Menominee" means "rice men" or "rice gatherers."
• Menominee County, Wisconsin: for the coterminous Menominee Indian Reservation
• Merced County, California: Spanish for "mercy", from Merced River, named by a traveler after a long dusty journey
• Mercer County, Illinois: is named for Hugh Mercer, an officer in the Continental Army killed in the Battle of Princeton
• Mercer County, Kentucky: named for Hugh Mercer
• Mercer County, Missouri: Named for John F. Mercer, a Revolutionary War general.
• Mercer County, New Jersey: named for Hugh Mercer
• Mercer County, North Dakota: Named for William Henry Harrison Mercer, an early rancher
• Mercer County, Ohio: named for Hugh Mercer
• Mercer County, Pennsylvania: named for Hugh Mercer
• Mercer County, West Virginia: named for Hugh Mercer
• Meriwether County, Georgia: named for General David Meriwether, who served in the Revolutionary War and was a state legislator and a member of congress.
• Merrick County, Nebraska: named for Elvira Merrick, wife of Henry W. DePuy, a territorial legislator
• Merrimack County, New Hampshire: named for The Merrimack River, probably of Native American origin, but conjectural.
• Mesa County, Colorado: Mesa County is named for Grand Mesa, a large flat-topped geologic formation near Grand Junction.
• Metcalfe County, Kentucky: named for Thomas Metcalfe, officer in the War of 1812, and Kentucky governor.
• Miami County, Indiana: named for the Miami Native American people.
• Miami County, Kansas: Miami Native American people.
• Miami County, Ohio: Miami Native American people.
• Miami-Dade County, Florida — An amalgamation of:
  • Miami, named after the Miami River, which in turn is believed to be derived from the Mayaimi, a Native American tribe that lived in South Florida until the 18th century.
  • Dade County, Florida, named after Major Francis L. Dade, a soldier killed in 1835 in the Second Seminole War.
• Middlesex County, Connecticut: Named after Middlesex, one of the historic counties of England.
• Middlesex County, Massachusetts: Named after Middlesex, one of the historic counties of England.

• Middlesex County, New Jersey: Named after Middlesex, one of the historic counties of England.

• Middlesex County, Virginia: Named after Middlesex, one of the historic counties of England.

• Midland County, Michigan: Named "Midland" because it is located near the geographical center of the Lower Peninsula.
• Midland County, Texas: named for its location midway between Fort Worth and El Paso on the Texas and Pacific Railroad
• Mifflin County, Pennsylvania: is named after the first governor of Pennsylvania, Thomas Mifflin.
• Milam County, Texas: named for Benjamin Rush Milam, an early Texas colonizer and soldier killed in the Texas Revolution
• Millard County, Utah: named for President Millard Fillmore
• Mille Lacs County, Minnesota Named for the French translation for a thousand lakes.
• Miller County, Arkansas: named for James Miller, the first governor of the Arkansas Territory and a Brigadier General during the War of 1812.
• Miller County, Georgia: named after Judge Andrew J. Miller, who served as a commander of the Oglethorpe Infantry
• Miller County, Missouri: for John Miller, governor of Missouri.
• Mills County, Iowa: named for Major Frederick Mills, killed in the Mexican-American War.
• Mills County, Texas: John T. Mills, an early judge in Texas
• Milwaukee County, Wisconsin: uncertain, but believed to be from a Potawatomi word "Mahnawaukee-Seepe" meaning "gathering place by the river."
• Miner County, South Dakota: named for territorial legislators Nelson Miner and Ephriam Miner.
• Mineral County, Colorado: Mineral County is named for the rich mineral ores found in the county, particularly the silver deposits located near the county seat of Creede.
• Mineral County, Montana: Mineral, for economically valuable mineral resources.
• Mineral County, Nevada: Mineral, for economically valuable mineral resources.
• Mineral County, West Virginia: Mineral, for economically valuable mineral resources, particularly coal.
• Mingo County, West Virginia: for the Mingo Indian tribe
• Minidoka County, Idaho:named for a Dakota Sioux word for "a fountain or spring of water"
• Minnehaha County, South Dakota: from a Native American word meaning river waterfall.
• Missaukee County, Michigan: Named for Ottawa chief Missaukee.
• Mississippi County, Arkansas: named for the Mississippi River, after the Ojibwe term for "great river"
• Mississippi County, Missouri, for Mississippi River
• Missoula County, Montana: a contraction of the Flathead word, "im-i-sul-e-etiku", meaning "near the place of fear"
• Mitchell County, Georgia: For Gen. Henry Mitchell , Revolutionary War hero and president of the GA Senate. Or possibly David Brydie Mitchell, GA governor.
• Mitchell County, Iowa: Named by Irish settlers for John Mitchel (sic), Irish nationalist who escaped to the U.S. .
• Mitchell County, Kansas: For Capt. William D. Mitchell, Union officer killed in the Civil War
• Mitchell County, North Carolina: For Elisha Mitchell, a mountain explorer of Mount Mitchell.
• Mitchell County, Texas: For Asa and Eli Mitchell, early settlers of Austin's colony.
• Mobile County, Alabama: From the Muskhogean name for the town of Mauvila, found by the first explorers.
• Modoc County, California: from the name of an Indian tribe
• Moffat County, Colorado: named for railroad tycoon and banker David Moffat
• Mohave County, Arizona: for the Mohave Indian tribe
• Moniteau County, Missouri: the French spelling of the Indian word meaning "spirit of God."
• Monmouth County, New Jersey: Named after Monmouthshire in Wales.
• Mono County, California:after Mono Lake, named for an Indian tribe, possibly from "monachie", meaning "fly people," an insect that formed part of their diet
• Monona County, Iowa: disputed, possibly the name of a legendary bereaved Indian girl who leaped into the Mississippi River; or the name of an Indian divinity; or Ottawa for 'beautiful land.'
• Monongalia County, West Virginia: Variant spelling for the Monongahela River, which means "unstable river banks"
• Monroe County, Alabama: All counties named Monroe in the USA are named for James Monroe, the fifth president of the United States.
• Monroe County, Arkansas: for James Monroe
• Monroe County, Florida: for James Monroe
• Monroe County, Georgia: for James Monroe
• Monroe County, Illinois: for James Monroe
• Monroe County, Indiana: for James Monroe.
• Monroe County, Iowa: for James Monroe
• Monroe County, Kentucky: for James Monroe
• Monroe County, Michigan: for James Monroe.
• Monroe County, Mississippi: for James Monroe
• Monroe County, Missouri: for James Monroe
• Monroe County, New York: for James Monroe
• Monroe County, Ohio: for James Monroe
• Monroe County, Pennsylvania: for James Monroe
• Monroe County, Tennessee: for James Monroe
• Monroe County, West Virginia: for James Monroe
• Monroe County, Wisconsin: for James Monroe
• Montague County, Texas: named for Daniel Montague, a state senator and early surveyor in the future county
• Montcalm County, Michigan: Named for Louis-Joseph de Montcalm.
• Monterey County, California: the Spanish words monte and rey, "king of the forest." The bay was named in honor of the Conde de Monterey, the Viceroy of New Spain.

• Montezuma County, Colorado: Montezuma County is named for the Aztec ruler Moctezuma II; the county's world-famous Mesa Verde ruins were once thought to have been built by the Aztecs.
• Montgomery County, Alabama: For Gen. Richard Montgomery, American Revolutionary War officer

• Montgomery County, Arkansas: Richard Montgomery
• Montgomery County, Georgia: Richard Montgomery
• Montgomery County, Illinois: Richard Montgomery
• Montgomery County, Indiana: Richard Montgomery
• Montgomery County, Iowa: Richard Montgomery
• Montgomery County, Kansas: For either James M. Montgomery,abolitionist and preacher; or for Richard Montgomery
• Montgomery County, Kentucky: Richard Montgomery
• Montgomery County, Maryland: Richard Montgomery
• Montgomery County, Mississippi: Richard Montgomery
• Montgomery County, Missouri: Richard Montgomery
• Montgomery County, New York: Richard Montgomery
• Montgomery County, North Carolina: Richard Montgomery
• Montgomery County, Ohio: Richard Montgomery
• Montgomery County, Pennsylvania: either for Richard Montgomery, or for the Welsh county of Montgomeryshire, named for Roger de Montgomerie, as that part of Pennsylvania was settled by Quakers from Wales
• Montgomery County, Tennessee: For John Montgomery explorer and Indian fighter.
• Montgomery County, Texas: Richard Montgomery
• Montgomery County, Virginia: Richard Montgomery
• Montmorency County, Michigan: For Count Raymond de Montmorency, a French officer who helped the colonies against England during the Revolutionary War.
• Montour County, Pennsylvania: Named for Madame Montour, a woman of Indian and French descent who was prominent in the Indian affairs
• Montrose County, Colorado: Montrose County is named for the town of Montrose, which itself is named after the novel A Legend of Montrose, by Sir Walter Scott.
• Moody County, South Dakota: Moody is named for territorial legislator and later U.S. Senator Gideon C. Moody.

• Moore County, North Carolina: For Capt. Alfred Moore, Revolutionary War officer, and U.S. Supreme Court justice
• Moore County, Tennessee: For Gen. William Moore,officer in the War of 1812 and later a state legislator.
• Moore County, Texas: For Edwin Ward Moore, a Republic of TX naval officer.
• Mora County, New Mexico: Either from names of early settlers, such as Mora Pineda and Garcia de la Mora, or possibly from the Spanish word meaning 'blackberry' or 'mulberry
• Morehouse Parish, Louisiana: named in honor of early settler Abraham Morehouse
• Morgan County, Alabama: For Gen. Daniel Morgan, an officer in the Revolutionary War and U.S. representative
• Morgan County, Colorado: Morgan County is named for the town of Fort Morgan (the county seat), which itself was named for United States Colonel Christopher A. Morgan, an aide to Civil War general John Pope.
• Morgan County, Georgia: for Daniel Morgan
• Morgan County, Illinois: for Daniel Morgan
• Morgan County, Indiana: Morgan is named for Daniel Morgan, an officer of the American Revolutionary War.
• Morgan County, Kentucky: for Daniel Morgan
• Morgan County, Missouri: for Daniel Morgan
• Morgan County, Ohio: for Daniel Morgan
• Morgan County, Tennessee: for Daniel Morgan
• Morgan County, Utah: For Jedediah Morgan Grant, prominent Mormon churchman.
• Morgan County, West Virginia: for Daniel Morgan
• Morrill County, Nebraska: named for Charles Henry Morrill, regent of the University of Nebraska
• Morris County, Kansas: For Thomas Morris, opponent of slavery and U.S. senator
• Morris County, New Jersey: Named for Col. Lewis Morris, colonial governor of the Province of New Jersey
• Morris County, Texas: For W.W. Morris, a prominent east TX attorney.
• Morrison County, Minnesota: For brothers William and Allen Morrison, fur traders
• Morrow County, Ohio: named for Jeremiah Morrow, U.S. senator and governor
• Morrow County, Oregon: maned for Jackson L. Morrow, member of the first state legislature.
• Morton County, Kansas: named for Oliver Hazard Perry Throck Morton (1823–77), jurist and U.S. senator
• Morton County, North Dakota: named for Oliver Hazard Perry Throck Morton
• Motley County, Texas: named for Junius William Mottley (sic), a signer of the Texas Declaration of Independence.
• Moultrie County, Illinois: For Gen. William Moultrie, an officer in the Revolutionary War and governor of South Carolina
• Mountrail County, North Dakota: For "Savage" Joseph Mountraille (sic), prominent voyageur who carried the mail.
• Mower County, Minnesota: For John Mower, territorial and state legislator
• Muhlenberg County, Kentucky: named for Peter Muhlenberg, clergyman, soldier during the Revolutionary War,
• Multnomah County, Oregon: For the Indian village on Sauvie Island; Lewis and Clark applied the name to all local Indians. From nemathlonamaq, probably meaning 'downriver.'
• Murray County, Georgia: For Thomas W. Murray legislator.
• Murray County, Minnesota: For William Pitt Murray, state legislator
• Murray County, Oklahoma: For William Henry Murray (1869–1956), U.S. representative and governor
• Muscatine County, Iowa: from the Mascouten tribe of the Potawatomi Indians, possibly meaning 'burning island.'
• Muscogee County, Georgia: for the native Muscogee people
• Muskegon County, Michigan: Named for the river. Derived from the Ojibwa/Chippewa word "mashkig," which means "swamp" or "marsh."
• Muskingum County, Ohio: from an Indian word for “near the river.” The Muskingum River flows through the county.
• Muskogee County, Oklahoma
• Musselshell County, Montana named for mussels found on the banks of the Musselshell River.

See also

• Lists of U.S. county name etymologies for links to the remainder of the list.