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
*Jackson County, Alabama
* Jackson County, Arkansas
* Jackson County, Colorado: Jackson County is named for United States President Andrew Jackson.
* Jackson County, Florida
* Jackson County, Georgia
* 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
* Jackson County, Kansas
* Jackson County, Kentucky
* Jackson County, Michigan
* Jackson County, Minnesota
* Jackson County, Mississippi
* Jackson County, Missouri
* Jackson County, North Carolina
* Jackson County, Ohio
* Jackson County, Oklahoma
* Jackson County, Oregon
* Jackson County, South Dakota
* Jackson County, Tennessee
* Jackson County, Texas
* Jackson County, West Virginia
* Jackson County, Wisconsin
* Jackson Parish, Louisiana
*James City County, Virginia
*Jasper County, Georgia
* 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
* Jasper County, Mississippi
* Jasper County, Missouri
* Jasper County, South Carolina
* Jasper County, Texas
*Jay County, Indiana: Jay is named for U.S. Secretary of State John Jay.
*Jeff Davis County, Georgia
* Jeff Davis County, Texas
*Jefferson County, Alabama
* Jefferson County, Arkansas
* 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
* Jefferson County, Georgia
* Jefferson County, Idaho
* 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
* Jefferson County, Kansas
* Jefferson County, Kentucky
* Jefferson County, Mississippi
* Jefferson County, Missouri
* Jefferson County, Montana
* Jefferson County, Nebraska
* Jefferson County, New York
* Jefferson County, Ohio
* Jefferson County, Oklahoma
* Jefferson County, Oregon
* Jefferson County, Pennsylvania
* Jefferson County, Tennessee
* Jefferson County, Texas
* Jefferson County, Washington
* Jefferson County, West Virginia
* Jefferson County, Wisconsin
* Jefferson Parish, Louisiana
*Jefferson Davis County, Mississippi
* Jefferson Davis Parish, Louisiana
*Jenkins County, Georgia
*Jennings County, Indiana: Jennings is named for Governor of Indiana Jonathan Jennings.
*Jerauld County, South Dakota
*Jerome County, Idaho
*Jersey County, Illinois: Jersey is named for the US state New Jersey.
*Jessamine County, Kentucky
*Jewell County, Kansas
*Jim Hogg County, Texas
*Jim Wells County, Texas
*Jo Daviess County, Illinois: Jo Daviess County is named after Joseph Hamilton Daviess, a soldier killed at the Battle of Tippecanoe.
*Johnson County, Arkansas
* Johnson County, Georgia
* Johnson County, Illinois
* Johnson County, Indiana: Johnson is named for John Johnson, a judge of the Indiana Supreme Court.
* Johnson County, Iowa
* Johnson County, Kansas
* Johnson County, Kentucky
* Johnson County, Missouri
* Johnson County, Nebraska
* Johnson County, Tennessee
* Johnson County, Texas
* Johnson County, Wyoming
*Johnston County, North Carolina
* Johnston County, Oklahoma
*Jones County, Georgia
* Jones County, Iowa
*Jones County, Mississippi
* Jones County, North Carolina
* Jones County, South Dakota
* Jones County, Texas
*Josephine County, Oregon
*Juab County, Utah
*Judith Basin County, Montana
*Juneau County, Wisconsin
*Juneau City and Borough, Alaska
*Juniata County, Pennsylvania
*Jupiter, Florida

K

*Kalamazoo County, Michigan
*Kalawao County, Hawaii
*Kalkaska County, Michigan
*Kanabec County, Minnesota
*Kanawha County, West Virginia
*Kandiyohi County, Minnesota
*Kane County, Illinois: Kane is named after U.S. senator Elias Kane.
*Kane County, Utah
*Kankakee County, Illinois: Kankakee County is named for the Kankakee River.
*Karnes County, Texas
*Kauai County, Hawaii
*Kaufman County, Texas
*Kay County, Oklahoma
*Kearney County, Nebraska
*Kearny County, Kansas
*Keith County, Nebraska
*Kemper County, Mississippi
*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
*Kenedy County, Texas
*Kennebec County, Maine
*Kenosha County, Wisconsin
*Kent County, Delaware
* Kent County, Maryland
* Kent County, Michigan
* Kent County, Rhode Island
* Kent County, Texas
*Kenton County, Kentucky
*Keokuk County, Iowa
*Kern County, California
*Kerr County, Texas
*Kershaw County, South Carolina
*Ketchikan Gateway Borough, Alaska
*Kewaunee County, Wisconsin
*Keweenaw County, Michigan
*Keya Paha County, Nebraska
*Kidder County, North Dakota
*Kimball County, Nebraska
*Kimble County, Texas
*King County, Texas
*King County, Washington: King County was named for William Rufus King, but was 'renamed' in honor of Dr. Martin Luther King, Jr. in 2005.
*King George County, Virginia
*King William County, Virginia
*King and Queen County, Virginia
*Kingfisher County, Oklahoma
*Kingman County, Kansas
*Kings County, California
*Kings County, New York: Named in honor of King Charles II of England.
*Kingsbury County, South Dakota
*Kinney County, Texas
*Kiowa County, Colorado: Kiowa County is named for the Kiowa Native American tribe.
* Kiowa County, Kansas
* Kiowa County, Oklahoma
*Kit Carson County, Colorado: Kit Carson County is named for explorer, trapper, and "Wild West" figure Kit Carson.
*Kitsap County, Washington
*Kittitas County, Washington
*Kittson County, Minnesota
*Klamath County, Oregon
*Kleberg County, Texas
*Klickitat County, Washington
*Knott County, Kentucky
*Knox County, Illinois: Knox is named after Revolutionary War General Henry Knox, who became the first United States Secretary of War.
* Knox County, Indiana: Knox is named for U.S. Secretary of War Henry Knox.
* Knox County, Kentucky
* Knox County, Maine
* Knox County, Missouri
* Knox County, Nebraska
* Knox County, Ohio
* Knox County, Tennessee
* Knox County, Texas
*Kodiak Island Borough, Alaska
*Koochiching County, Minnesota
*Kootenai County, Idaho
*Kosciusko County, Indiana: Kosciusko is named for Tadeusz Kościuszko, a Polish ally of the Americans during the Revolutionary War.
*Kossuth County, Iowa

L

*La Crosse County, Wisconsin
*La Moure County, North Dakota
*La Paz County, Arizona
*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
* La Salle County, Texas
* La Salle Parish, Louisiana
*Labette County, Kansas
*Lac qui Parle County, Minnesota
*Lackawanna County, Pennsylvania
*Laclede County, Missouri
*Lafayette County, Arkansas
* 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
* 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
* Lake County, Indiana: Lake is named for its location on Lake Michigan.
* Lake County, Michigan
* Lake County, Minnesota
* Lake County, Montana
* Lake County, Ohio: Lake is named for its location on Lake Erie.
* Lake County, Oregon
* Lake County, South Dakota
* Lake County, Tennessee
*Lake and Peninsula Borough, Alaska
*Lake of the Woods County, Minnesota
*Lamar County, Alabama
* Lamar County, Georgia
* Lamar County, Mississippi
* Lamar County, Texas
*Lamb County, Texas
*Lamoille County, Vermont
*Lampasas County, Texas
*Lancaster County, Nebraska
* Lancaster County, Pennsylvania
* Lancaster County, South Carolina
* Lancaster County, Virginia
*Lander County, Nevada
*Lane County, Kansas
* Lane County, Oregon
*Langlade County, Wisconsin
*Lanier County, Georgia
*Lapeer County, Michigan
*Laramie County, Wyoming
*Larimer County, Colorado: Larimer County is named for "General" William Larimer, Jr., the founder of Denver, Colorado.
*Larue County, Kentucky
*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
*Latah County, Idaho
*Latimer County, Oklahoma
*Lauderdale County, Alabama
* Lauderdale County, Mississippi
* Lauderdale County, Tennessee
*Laurel County, Kentucky — Named for the mountain laurel trees common in the area.
*Laurens County, Georgia
* Laurens County, South Carolina
*Lavaca County, Texas
*Lawrence County, Alabama
* Lawrence County, Arkansas
* Lawrence County, Illinois
* Lawrence County, Indiana: Lawrence is named for U.S. naval leader James Lawrence.
* Lawrence County, Kentucky
* Lawrence County, Mississippi
* Lawrence County, Missouri
* Lawrence County, Ohio
* Lawrence County, Pennsylvania
* Lawrence County, South Dakota
* Lawrence County, Tennessee
*Le Flore County, Oklahoma
*Le Sueur County, Minnesota
*Lea County, New Mexico
*Leake County, Mississippi
*Leavenworth County, Kansas
*Lebanon County, Pennsylvania
*Lee County, Alabama
* Lee County, Arkansas
* Lee County, Florida
* Lee County, Georgia
* Lee County, Illinois
* Lee County, Iowa
* Lee County, Kentucky
* Lee County, Mississippi
* Lee County, North Carolina
* Lee County, South Carolina
* Lee County, Texas
* Lee County, Virginia
*Leelanau County, Michigan
*Leflore County, Mississippi
*Lehigh County, Pennsylvania
*Lemhi County, Idaho
*Lenawee County, Michigan
*Lenoir County, North Carolina
*Leon County, Florida
* Leon County, Texas
*Leslie County, Kentucky
*Letcher County, Kentucky
*Levy County, Florida
*Lewis County, Idaho
* Lewis County, Kentucky
* Lewis County, Missouri
* Lewis County, New York
* Lewis County, Tennessee
* Lewis County, Washington
* Lewis County, West Virginia
*Lewis and Clark County, Montana
*Lexington, Virginia
*Lexington County, South Carolina
*Liberty County, Florida
* Liberty County, Georgia
* Liberty County, Montana
* Liberty County, Texas
*Licking County, Ohio
*Limestone County, Alabama,
* Limestone County, Texas
*Lincoln County, Arkansas
* Lincoln County, Colorado: Lincoln County is named for United States President Abraham Lincoln.
* Lincoln County, Georgia
* Lincoln County, Idaho
* Lincoln County, Kansas
* Lincoln County, Kentucky
* Lincoln County, Maine
* Lincoln County, Minnesota
* Lincoln County, Mississippi
* Lincoln County, Missouri
* Lincoln County, Montana
* Lincoln County, Nebraska
* Lincoln County, Nevada
* Lincoln County, New Mexico
* Lincoln County, North Carolina
* Lincoln County, Oklahoma
* Lincoln County, Oregon
* Lincoln County, South Dakota
* Lincoln County, Tennessee
* Lincoln County, Washington
* Lincoln County, West Virginia
* Lincoln County, Wisconsin
* Lincoln County, Wyoming
* Lincoln Parish, Louisiana
*Linn County, Iowa
* Linn County, Kansas
* Linn County, Missouri
* Linn County, Oregon
*Lipscomb County, Texas
*Litchfield County, Connecticut
*Little River County, Arkansas
*Live Oak County, Texas
*Livingston County, Illinois
* Livingston County, Kentucky
* Livingston County, Michigan
* Livingston County, Missouri
* Livingston County, New York
* Livingston Parish, Louisiana
*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
* Logan County, Kansas
* Logan County, Kentucky
* Logan County, Nebraska
* Logan County, North Dakota
* Logan County, Ohio
* Logan County, Oklahoma
* Logan County, West Virginia
*Long County, Georgia
*Lonoke County, Arkansas
*Lorain County, Ohio: Lorain County was named after the province of Lorraine, France
*Los Alamos County, New Mexico
*Los Angeles County, California
*Loudon County, Tennessee
*Loudoun County, Virginia
*Louisa County, Iowa
* Louisa County, Virginia
*Loup County, Nebraska
*Love County, Oklahoma
*Loving County, Texas
*Lowndes County, Alabama
* Lowndes County, Georgia - William Lowndes
* Lowndes County, Mississippi
*Lubbock County, Texas
*Lucas County, Iowa
* Lucas County, Ohio
*Luce County, Michigan
*Lumpkin County, Georgia
*Luna County, New Mexico
*Lunenburg County, Virginia
*Luzerne County, Pennsylvania
*Lycoming County, Pennsylvania
*Lyman County, South Dakota
*Lynchburg, Virginia
*Lynn County, Texas
*Lyon County, Iowa
* Lyon County, Kansas
* Lyon County, Kentucky
* Lyon County, Minnesota
* Lyon County, Nevada

M

*Mackinac County, Michigan
*Macomb County, Michigan
*Macon County, Alabama
* Macon County, Georgia
* Macon County, Illinois
* Macon County, Missouri
* Macon County, North Carolina
* Macon County, Tennessee
*Macoupin County, Illinois
*Madera County, California
*Madison County, Alabama
* Madison County, Arkansas
* Madison County, Florida
* Madison County, Georgia
* Madison County, Idaho
* Madison County, Illinois
* Madison County, Indiana: Madison is named for U.S. President James Madison.
* Madison County, Iowa
* Madison County, Kentucky
* Madison County, Mississippi
* Madison County, Missouri
* Madison County, Montana
* Madison County, Nebraska
* Madison County, New York
* Madison County, North Carolina
* Madison County, Ohio
* Madison County, Tennessee
* Madison County, Texas
* Madison County, Virginia
* Madison Parish, Louisiana
*Magoffin County, Kentucky
*Mahaska County, Iowa
*Mahnomen County, Minnesota
*Mahoning County, Ohio
*Major County, Oklahoma
*Malheur County, Oregon
*Manassas, Virginia
*Manassas Park, Virginia
*Manatee County, Florida
*Manistee County, Michigan
*Manitowoc County, Wisconsin
*Marathon County, Wisconsin
*Marengo County, Alabama
*Maricopa County, Arizona
*Maries County, Missouri
*Marin County, California
*Marinette County, Wisconsin
*Marion County, Alabama: Marion is named for Francis Marion, the "Swamp Fox" of the American Revolutionary War.
* Marion County, Arkansas: Marion is named for Francis Marion, the "Swamp Fox" of the American Revolutionary War.
* Marion County, Florida: Marion is named for Francis Marion, the "Swamp Fox" of the American Revolutionary War.
* Marion County, Georgia: Marion is named for Francis Marion, the "Swamp Fox" of the American Revolutionary War.
* Marion County, Illinois
* Marion County, Indiana: Marion is named for Francis Marion, the "Swamp Fox" of the American Revolutionary War.
* Marion County, Iowa: Marion is named for Francis Marion, the "Swamp Fox" of the American Revolutionary War.
* Marion County, Kansas for Marion County, Ohio
* Marion County, Kentucky: Marion is named for Francis Marion, the "Swamp Fox" of the American Revolutionary War.
* Marion County, Mississippi
* Marion County, Missouri
* Marion County, Ohio : Marion is named for Francis Marion, the "Swamp Fox" of the American Revolutionary War.
* Marion County, Oregon: Marion is named for Francis Marion, the "Swamp Fox" of the American Revolutionary War.
* Marion County, South Carolina: Marion is named for Francis Marion, the "Swamp Fox" of the American Revolutionary War.
* Marion County, Tennessee: Marion is named for Francis Marion, the "Swamp Fox" of the American Revolutionary War.
* Marion County, Texas: Marion is named for Francis Marion, the "Swamp Fox" of the American Revolutionary War.
*Marion County, West Virginia: Marion is named for Francis Marion, the "Swamp Fox" of the American Revolutionary War.
*Mariposa County, California
*Marlboro County, South Carolina
*Marquette County, Michigan
* Marquette County, Wisconsin
*Marshall County, Alabama
* Marshall County, Illinois
* Marshall County, Indiana: Marshall is named for U.S. Chief Justice John Marshall.
* Marshall County, Iowa
*Marshall County, Kansas
* Marshall County, Kentucky
* Marshall County, Minnesota
* Marshall County, Mississippi
* Marshall County, Oklahoma
* Marshall County, South Dakota
* Marshall County, Tennessee
* Marshall County, West Virginia
*Martin County, Florida
* Martin County, Indiana: Martin is named for Maj. John T. Martin of Kentucky
* Martin County, Kentucky
* Martin County, Minnesota
* Martin County, North Carolina
* Martin County, Texas
*Martinsville, Virginia
*Mason County, Illinois
* Mason County, Kentucky
* Mason County, Michigan
* Mason County, Texas
* Mason County, Washington
* Mason County, West Virginia
*Massac County, Illinois
*Matagorda County, Texas
*Matanuska-Susitna Borough, Alaska
*Mathews County, Virginia
*Maui County, Hawaii
*Maury County, Tennessee
*Maverick County, Texas
*Mayes County, Oklahoma
*McClain County, Oklahoma
*McCone County, Montana
*McCook County, South Dakota
*McCormick County, South Carolina
*McCracken County, Kentucky
*McCreary County, Kentucky
*McCulloch County, Texas
*McCurtain County, Oklahoma
*McDonald County, Missouri
*McDonough County, Illinois
*McDowell County, North Carolina
* McDowell County, West Virginia
*McDuffie County, Georgia
*McHenry County, Illinois
* McHenry County, North Dakota
*McIntosh County, Georgia
* McIntosh County, North Dakota
* McIntosh County, Oklahoma
*McKean County, Pennsylvania
*McKenzie County, North Dakota
*McKinley County, New Mexico
*McLean County, Illinois
* McLean County, Kentucky
* McLean County, North Dakota
*McLennan County, Texas
*McLeod County, Minnesota
*McMinn County, Tennessee
*McMullen County, Texas
*McNairy County, Tennessee
*McPherson County, Kansas
* McPherson County, Nebraska
* McPherson County, South Dakota
*Meade County, Kansas
* Meade County, Kentucky
* Meade County, South Dakota
* Meagher County, Montana
*Mecklenburg County, North Carolina
* Mecklenburg County, Virginia
*Mecosta County, Michigan
*Medina County, Ohio
* Medina County, Texas
*Meeker County, Minnesota
*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
*Menard County, Illinois
* Menard County, Texas
*Mendocino County, California
*Menifee County, Kentucky
*Menominee County, Michigan
* Menominee County, Wisconsin
*Merced County, California
*Mercer County, Illinois
* Mercer County, Kentucky
* Mercer County, Missouri
* Mercer County, New Jersey is named for Hugh Mercer, an officer in the Continental Army killed in the Battle of Princeton
* Mercer County, North Dakota
* Mercer County, Ohio
* Mercer County, Pennsylvania
* Mercer County, West Virginia
*Meriwether County, Georgia
*Merrick County, Nebraska
*Merrimack County, New Hampshire
*Mesa County, Colorado: Mesa County is named for Grand Mesa, a large flat-topped geologic formation near Grand Junction.
*Metcalfe County, Kentucky
*Miami County, Indiana: Miami is named for the Miami Native American people.
* Miami County, Kansas
* Miami County, Ohio
*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
* Middlesex County, Massachusetts
* Middlesex County, New Jersey
* Middlesex County, Virginia
*Midland County, Michigan
* Midland County, Texas
*Mifflin County, Pennsylvania
*Milam County, Texas
*Millard County, Utah
*Mille Lacs County, Minnesota
*Miller County, Arkansas
* Miller County, Georgia
* Miller County, Missouri
*Mills County, Iowa
* Mills County, Texas
*Milwaukee County, Wisconsin
*Miner County, South Dakota
*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 County, Nevada
* Mineral County, West Virginia
*Mingo County, West Virginia
*Minidoka County, Idaho
*Minnehaha County, South Dakota
*Missaukee County, Michigan
*Mississippi County, Arkansas
* Mississippi County, Missouri
*Missoula County, Montana
*Mitchell County, Georgia
* Mitchell County, Iowa
* Mitchell County, Kansas
* Mitchell County, North Carolina
* Mitchell County, Texas
*Mobile County, Alabama
*Modoc County, California
*Moffat County, Colorado: Moffat County is named for railroad tycoon and banker David Moffat, who died less than three weeks after the county was named in his honor.
*Mohave County, Arizona
*Moniteau County, Missouri
*Monmouth County, New Jersey
*Mono County, California
*Monona County, Iowa
*Monongalia County, West Virginia
*Monroe County, Alabama
* Monroe County, Arkansas
* Monroe County, Florida
* Monroe County, Georgia
* Monroe County, Illinois
* Monroe County, Indiana: Monroe is named for U.S. President James Monroe.
* Monroe County, Iowa
* Monroe County, Kentucky
* Monroe County, Michigan
* Monroe County, Mississippi
* Monroe County, Missouri
* Monroe County, New York
* Monroe County, Ohio
* Monroe County, Pennsylvania
* Monroe County, Tennessee
* Monroe County, West Virginia
* Monroe County, Wisconsin
*Montague County, Texas
*Montcalm County, Michigan
*Monterey County, California
*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
* Montgomery County, Arkansas
* Montgomery County, Georgia
* Montgomery County, Illinois
* Montgomery County, Indiana: Montgomery is named for Richard Montgomery, an officer of the American Revolutionary War.
* Montgomery County, Iowa
* Montgomery County, Kansas
* Montgomery County, Kentucky
* Montgomery County, Maryland
* Montgomery County, Mississippi
* Montgomery County, Missouri
* Montgomery County, New York
* Montgomery County, North Carolina
* Montgomery County, Ohio
* Montgomery County, Pennsylvania
* Montgomery County, Tennessee
* Montgomery County, Texas
* Montgomery County, Virginia
*Montmorency County, Michigan
*Montour County, Pennsylvania
*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
*Moore County, North Carolina
* Moore County, Tennessee
* Moore County, Texas
*Mora County, New Mexico
*Morehouse Parish, Louisiana
*Morgan County, Alabama
* 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
* Morgan County, Illinois
* Morgan County, Indiana: Morgan is named for Daniel Morgan, an officer of the American Revolutionary War.
* Morgan County, Kentucky
* Morgan County, Missouri
* Morgan County, Ohio
* Morgan County, Tennessee
* Morgan County, Utah
* Morgan County, West Virginia
*Morrill County, Nebraska
*Morris County, Kansas
* Morris County, New Jersey
* Morris County, Texas
*Morrison County, Minnesota
*Morrow County, Ohio
* Morrow County, Oregon
*Morton County, Kansas
*Morton County, North Dakota
*Motley County, Texas
*Moultrie County, Illinois
*Mountrail County, North Dakota
*Mower County, Minnesota
*Muhlenberg County, Kentucky
*Multnomah County, Oregon
*Murray County, Georgia
* Murray County, Minnesota
* Murray County, Oklahoma
*Muscatine County, Iowa
*Muscogee County, Georgia
*Muskegon County, Michigan
*Muskingum County, Ohio
*Muskogee County, Oklahoma
*Musselshell County, Montana

ee also

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