| Number | Name of county | Count[1] | Most commonly named after |
| 1 | Washington County | 31 | George Washington |
| 2 | Jefferson County | 26 | Thomas Jefferson |
| 3 | Franklin County | 25 | Benjamin Franklin |
| 4 | Jackson County | 24 | Andrew Jackson |
| 4 | Lincoln County | 24 | Abraham Lincoln, Benjamin Lincoln (6) |
| 6 | Madison County | 20 | James Madison |
| 7 | Clay County | 18 | Henry Clay |
| 7 | Montgomery County | 18 | Richard Montgomery |
| 7 | Union County | 18 | The Union of the States or union of parts of adjoining counties |
| 10 | Marion County | 17 | Francis Marion |
| 10 | Monroe County | 17 | James Monroe |
| 12 | Greene County | 16 | Nathanael Greene. See also Green County. |
| 12 | Wayne County | 16 | Anthony Wayne |
| 14 | Grant County | 15 | Ulysses S. Grant |
| 15 | Warren County | 14 | Joseph Warren |
| 16 | Carroll County | 13 | Charles Carroll of Carrollton |
| 17 | Adams County | 12 | John Adams or John Quincy Adams |
| 17 | Clark County | 12 | William Clark or George Rogers Clark. See also Clarke County. |
| 17 | Douglas County | 12 | Stephen A. Douglas |
| 17 | Johnson County | 12 | Richard M. Johnson |
| 17 | Lake County | 12 | Geographical feature |
| 17 | Lee County | 12 | Robert E. Lee or Henry "Light-Horse Harry" Lee |
| 17 | Marshall County | 12 | John Marshall |
| 17 | Polk County | 12 | James K. Polk |
| 25 | Calhoun County | 11 | John C. Calhoun |
| 25 | Crawford County | 11 | William H. Crawford or Col. William Crawford |
| 25 | Fayette County | 11 | Marquis de la Fayette |
| 25 | Lawrence County | 11 | James Lawrence |
| 25 | Morgan County | 11 | Daniel Morgan or Fort Morgan/Col. Christopher A. Morgan (Colorado) (1) |
| 25 | Scott County | 11 | Winfield Scott or Charles Scott |
| 31 | Hamilton County | 10 | Alexander Hamilton |
| 31 | Hancock County | 10 | John Hancock |
| 31 | Henry County | 10 | Patrick Henry or Col. Henry Dodge (Iowa) |
| 31 | Logan County | 10 | John A. Logan or Benjamin Logan |
| 31 | Perry County | 10 | Oliver Hazard Perry |
| 31 | Pike County | 10 | Zebulon Pike |
| 37 | Benton County | 9 | Thomas Hart Benton |
| 37 | Brown County | 9 | Jacob Brown |
| 37 | Cass County | 9 | Lewis Cass |
| 37 | Clinton County | 9 | George Clinton or DeWitt Clinton |
| 37 | Knox County | 9 | Henry Knox |
| 37 | Putnam County | 9 | Israel Putnam |
| 37 | Shelby County | 9 | Isaac Shelby |
| 44 | Boone County | 8 | Daniel Boone |
| 44 | Butler County | 8 | William O. Butler or Richard Butler |
| 44 | Cherokee County | 8 | Cherokee tribe |
| 44 | Columbia County | 8 | Columbia (poetic name for America) |
| 44 | Cumberland County | 8 | Prince William, Duke of Cumberland |
| 44 | Fulton County | 8 | Robert Fulton |
| 44 | Harrison County | 8 | William Henry Harrison |
| 44 | Jasper County | 8 | William Jasper |
| 44 | Mercer County | 8 | Hugh Mercer |
| 44 | Orange County | 8 | the fruit or Prince of Orange |
| 44 | Randolph County | 8 | Edmund Randolph or John Randolph of Roanoke |
| 44 | Webster County | 8 | Daniel Webster |
| 56 | Howard County | 7 | Tilghman Howard, John Eager Howard, or Oliver Otis Howard |
| 56 | Lewis County | 7 | Meriwether Lewis or Morgan Lewis (New York) |
| 56 | Pulaski County | 7 | Kazimierz Pułaski |
| 56 | Richland County | 7 | fertile soil |
| 56 | Taylor County | 7 | Zachary Taylor |
| 61 | Custer County | 6 | George Armstrong Custer |
| 61 | DeKalb County | 6 | Johann de Kalb |
| 61 | Delaware County | 6 | Delaware (tribe) (3) |
| 61 | Lafayette County | 6 | Marquis de Lafayette |
| 61 | Floyd County | 6 | John Floyd |
| 61 | Garfield County | 6 | James A. Garfield |
| 61 | Hardin County | 6 | John Hardin, John J. Hardin, or Joseph Hardin Sr. |
| 61 | Jones County | 6 | Each county is named after a different person. |
| 61 | Livingston County | 6 | Edward Livingston (4) |
| 61 | Macon County | 6 | Nathaniel Macon |
| 61 | Martin County | 6 | Each county is named after a different person. |
| 61 | Mason County | 6 | George Mason (3) |
| 61 | Newton County | 6 | Sgt. John Newton (4) |
| 61 | Sullivan County | 6 | John Sullivan |
| 75 | Allen County | 5 | John Allen |
| 75 | Anderson County | 5 | Each county is named after a different person. |
| 75 | Caldwell County | 5 | John Caldwell (2) |
| 75 | Campbell County | 5 | Robert Campbell (Wyoming) |
| 75 | Carter County | 5 | Each county is named after a different person. |
| 75 | Dallas County | 5 | Alexander J. Dallas (Alabama); George M. Dallas |
| 75 | Decatur County | 5 | Stephen Decatur |
| 75 | Essex County | 5 | County of Essex in England |
| 75 | Henderson County | 5 | Richard Henderson (2) |
| 75 | Houston County | 5 | Sam Houston; George S. Houston; John Houstoun |
| 75 | Kent County | 5 | County of Kent in England |
| 75 | Lyon County | 5 | Nathaniel Lyon, except for Lyon County, Kentucky, which is named for Chittenden Lyon |
| 75 | Mitchell County | 5 | Each county is named after a different person. |
| 75 | Pierce County | 5 | Franklin Pierce |
| 75 | Saline County | 5 | Saltwater springs; the Saline River |
| 75 | Sheridan County | 5 | Philip Sheridan |
| 75 | White County | 5 | Isaac White (2) |
| 75 | York County | 5 | James, Duke of York (later King James II); city of York, England |
| 94 | Adair County | 4 | John Adair |
| 94 | Allegheny County | 4 | Allegheny Mountains and Allegheny River |
| 94 | Blaine County | 4 | James Blaine |
| 94 | Camden County | 4 | Charles Pratt, 1st Earl Camden |
| 94 | Carbon County | 4 | Coal deposits |
| 94 | Dawson County | 4 | Each county is named after a different person. |
| 94 | Dodge County | 4 | Henry Dodge |
| 94 | Fremont County | 4 | John C. Frémont |
| 94 | Grundy County | 4 | Felix Grundy |
| 94 | Iron County | 4 | Iron ore deposits |
| 94 | Lamar County | 4 | Lucius Quintus Cincinnatus Lamar (except for Lamar County, Texas) |
| 94 | Lancaster County | 4 | Lancaster, Lancashire |
| 94 | Liberty County | 4 | Liberty |
| 94 | Linn County | 4 | Lewis F. Linn |
| 94 | Middlesex County | 4 | Historic county of Middlesex in England |
| 94 | Mineral County | 4 | Mineral deposits |
| 94 | Ottawa County | 4 | Odawa people |
| 94 | Phillips County | 4 | Each county is named after a different person. |
| 94 | Richmond County | 4 | Duke of Richmond |
| 94 | Russell County | 4 | Each county is named after a different person. |
| 94 | San Juan County | 4 | San Juan River (Colorado River tributary) (3) |
| 94 | Sherman County | 4 | William Tecumseh Sherman, except Sherman County, Texas, named for Sidney Sherman |
| 94 | Smith County | 4 | Each county is named after a different person. |
| 94 | Somerset County | 4 | County of Somerset in England |
| 94 | St. Clair County | 4 | Arthur St. Clair, except St. Clair County, Michigan, named for St. Clare of Assisi |
| 94 | Sumter County | 4 | Thomas Sumter |
| 94 | Van Buren County | 4 | Martin Van Buren |
| 94 | Wheeler County | 4 | Each county is named after a different person. |
| 94 | Wilson County | 4 | Each county is named after a different person. |
| 94 | Wood County | 4 | Each county is named after a different person. |
| 123 | Baker County | 3 | Each county is named after a different person. |
| 123 | Beaver County | 3 | Beaver |
| 123 | Bedford County | 3 | Bedfordshire (a county in England) |
| 123 | Buchanan County | 3 | James Buchanan |
| 123 | Buffalo County | 3 | Buffalo; Buffalo River (Wisconsin) |
| 123 | Burke County | 3 | Each county is named after a different person. |
| 123 | Butte County | 3[2] | Butte (natural feature) |
| 123 | Cameron County | 3 | Each county is named after a different person. |
| 123 | Cedar County | 3 | Cedar |
| 123 | Chester County | 3 | Chester, England (2), Robert I. Chester (1) |
| 123 | Cheyenne County | 3 | Cheyenne people |
| 123 | Chippewa County | 3 | Ojibwa people |
| 123 | Choctaw County | 3 | Choctaw people |
| 123 | Christian County | 3 | William Christian |
| 123 | Claiborne County | 3 | William C. C. Claiborne |
| 123 | Cleveland County | 3 | Grover Cleveland (2) |
| 123 | Coffee County | 3 | John Coffee |
| 123 | Comanche County | 3 | Comanche people |
| 123 | Cook County | 3 | |
| 123 | Daviess County | 3 | Joseph Hamilton Daveiss |
| 123 | Delta County | 3 | |
| 123 | DeSoto County | 3 | Hernando de Soto |
| 123 | Dickinson County | 3 | |
| 123 | Edwards County | 3 | |
| 123 | Ellis County | 3 | |
| 123 | Erie County | 3 | Lake Erie, Erie people |
| 123 | Fairfield County | 3 | The beauty of the fields in these areas |
| 123 | Gallatin County | 3 | Albert Gallatin |
| 123 | Graham County | 3 | |
| 123 | Grayson County | 3 | |
| 123 | Hall County | 3 | |
| 123 | Haskell County | 3 | |
| 123 | Holmes County | 3 | |
| 123 | Humboldt County | 3 | Alexander von Humboldt |
| 123 | Kiowa County | 3 | Kiowa people |
| 123 | LaSalle County | 3 | René-Robert Cavelier, Sieur de La Salle |
| 123 | Lauderdale County | 3 | James Lauderdale |
| 123 | Lowndes County | 3 | William Jones Lowndes |
| 123 | McIntosh County | 3 | |
| 123 | McLean County | 3 | |
| 123 | McPherson County | 3 | James B. McPherson |
| 123 | Meade County | 3 | George Gordon Meade |
| 123 | Miami County | 3 | Miami people |
| 123 | Miller County | 3 | |
| 123 | Moore County | 3 | |
| 123 | Morris County | 3 | |
| 123 | Murray County | 3 | |
| 123 | Nelson County | 3 | Thomas Nelson Jr. |
| 123 | Noble County | 3 | |
| 123 | Northampton County | 3 | Northamptonshire, England (2) |
| 123 | Ohio County | 3 | Ohio River |
| 123 | Oneida County | 3 | Oneida people (2) |
| 123 | Orleans County | 3 | |
| 123 | Osage County | 3 | Osage people |
| 123 | Osceola County | 3 | Osceola |
| 123 | Park County | 3 | South Park and Yellowstone |
| 123 | Pawnee County | 3 | Pawnee people |
| 123 | Pickens County | 3 | Andrew Pickens |
| 123 | Platte County | 3 | Platte River |
| 123 | Pope County | 3 | |
| 123 | Pottawatomie County | 3 | Potawatomi people |
| 123 | Potter County | 3 | |
| 123 | Robertson County | 3 | |
| 123 | Rock County | 3 | |
| 123 | Rockingham County | 3 | Charles Watson-Wentworth, 2nd Marquess of Rockingham |
| 123 | Schuyler County | 3 | Philip Schuyler |
| 123 | Seminole County | 3 | Seminole people |
| 123 | Sevier County | 3 | |
| 123 | Sioux County | 3 | Sioux people |
| 123 | Stark County | 3 | |
| 123 | Stephens County | 3 | |
| 123 | Stevens County | 3 | Thaddeus Stevens (Kansas) ; Isaac Stevens (2) |
| 123 | Stone County | 3 | |
| 123 | Summit County | 3 | Summits (geographical feature) |
| 123 | Sussex County | 3 | County of Sussex in England |
| 123 | Teton County | 3 | Teton River (Montana); Teton Range |
| 123 | Thomas County | 3 | |
| 123 | Todd County | 3 | |
| 123 | Valley County | 3 | Valleys (geographical feature) |
| 123 | Vermilion County | 3 | Vermilion River |
| 123 | Vernon County | 3 | Mount Vernon |
| 123 | Walker County | 3 | Samuel Walker (Texas) |
| 123 | Williamson County | 3 | |
| 123 | Winnebago County | 3 | Winnebago people |
| 123 | Worth County | 3 | William J. Worth |
| 123 | Wright County | 3 | Silas Wright |
| 123 | Wyoming County | 3 | Delaware Indian word meaning "wide plains"; Wyoming Valley |
| 210 | Albany County | 2 | |
| 210 | Alexander County | 2 | |
| 210 | Armstrong County | 2 | |
| 210 | Ashland County | 2 | The Lexington estate of Henry Clay |
| 210 | Atchison County | 2 | David Rice Atchison |
| 210 | Baldwin County | 2 | Abraham Baldwin |
| 210 | Barry County | 2 | William T. Barry |
| 210 | Barton County | 2 | Clara Barton (KS); David Barton (MO) |
| 210 | Bath County | 2 | |
| 210 | Barbour County | 2 | James Barbour (AL); Philip P. Barbour (WV) |
| 210 | Bay County | 2 | |
| 210 | Beaufort County | 2 | Henry, Duke of Beaufort |
| 210 | Beckham County | 2 | J. C. W. Beckham |
| 210 | Bell County | 2 | |
| 210 | Berkeley County | 2 | |
| 210 | Berrien County | 2 | John M. Berrien |
| 210 | Bibb County | 2 | William W. Bibb |
| 210 | Big Horn County | 2 | Big Horn River |
| 210 | Blount County | 2 | William Blount |
| 210 | Bourbon County | 2 | |
| 210 | Boyd County | 2 | |
| 210 | Bradford County | 2 | |
| 210 | Bradley County | 2 | |
| 210 | Bristol County | 2 | |
| 210 | Brooks County | 2 | |
| 210 | Brunswick County | 2 | Duchy of Brunswick-Lüneburg |
| 210 | Bryan County | 2 | |
| 210 | Burnett County | 2 | |
| 210 | Caddo County | 2 | Caddo people |
| 210 | Caroline County | 2 | |
| 210 | Chambers County | 2 | |
| 210 | Champaign County | 2 | |
| 210 | Charlotte County | 2 | |
| 210 | Chase County | 2 | |
| 210 | Chatham County | 2 | |
| 210 | Chautauqua County | 2 | |
| 210 | Chesterfield County | 2 | |
| 210 | Chickasaw County | 2 | Chickasaw people |
| 210 | Clayton County | 2 | |
| 210 | Clearwater County | 2 | |
| 210 | Cleburne County | 2 | Patrick Cleburne |
| 210 | Colfax County | 2 | Schuyler Colfax |
| 210 | Coos County | 2 | |
| 210 | Covington County | 2 | |
| 210 | Craig County | 2 | |
| 210 | Crittenden County | 2 | |
| 210 | Crockett County | 2 | David Crockett |
| 210 | Crook County | 2 | George Crook |
| 210 | Curry County | 2 | |
| 210 | Dade County | 2[3] | |
| 210 | Dakota County | 2 | Sioux people |
| 210 | Davidson County | 2 | |
| 210 | Davis County | 2 | |
| 210 | Deuel County | 2 | |
| 210 | Dewey County | 2 | |
| 210 | DeWitt County | 2 | DeWitt Clinton (Illinois); Green DeWitt (Texas) |
| 210 | Dorchester County | 2 | |
| 210 | Dunn County | 2 | |
| 210 | Duval County | 2 | |
| 210 | Eddy County | 2 | |
| 210 | Effingham County | 2 | |
| 210 | El Paso County | 2 | |
| 210 | Elbert County | 2 | |
| 210 | Elk County | 2 | Elk |
| 210 | Elmore County | 2 | |
| 210 | Emmet County | 2 | |
| 210 | Escambia County | 2 | Escambia River |
| 210 | Fannin County | 2 | James Fannin |
| 210 | Fillmore County | 2 | Millard Fillmore |
| 210 | Florence County | 2 | |
| 210 | Ford County | 2 | |
| 210 | Forest County | 2 | |
| 210 | Forsyth County | 2 | |
| 210 | Frederick County | 2 | |
| 210 | Genesee County | 2 | |
| 210 | Gibson County | 2 | |
| 210 | Giles County | 2 | |
| 210 | Gilmer County | 2 | |
| 210 | Gloucester County | 2 | County of Gloucestershire in England |
| 210 | Golden Valley County | 2 | |
| 210 | Grady County | 2 | |
| 210 | Grand County | 2 | Grand River |
| 210 | Gray County | 2 | |
| 210 | Greeley County | 2 | Horace Greeley |
| 210 | Greenwood County | 2 | |
| 210 | Guadalupe County | 2 | |
| 210 | Hale County | 2 | |
| 210 | Halifax County | 2 | |
| 210 | Hampshire County | 2 | County of Hampshire in England |
| 210 | Hardeman County | 2 | |
| 210 | Harding County | 2 | Warren Harding (New Mexico); J.A. Harding (South Dakota) |
| 210 | Harlan County | 2 | |
| 210 | Harper County | 2 | |
| 210 | Harris County | 2 | |
| 210 | Hart County | 2 | |
| 210 | Hayes County | 2 | Rutherford B. Hayes (Nebraska); John Coffee Hays (Texas) |
| 210 | Haywood County | 2 | |
| 210 | Hickman County | 2 | |
| 210 | Hidalgo County | 2 | Villa de Guadalupe (New Mexico); Miguel Hidalgo y Costilla (Texas) |
| 210 | Highland County | 2 | |
| 210 | Hill County | 2 | |
| 210 | Hillsborough County | 2 | |
| 210 | Holt County | 2 | |
| 210 | Hopkins County | 2 | |
| 210 | Hughes County | 2 | |
| 210 | Humphreys County | 2 | |
| 210 | Huron County | 2 | Lake Huron (Michigan) ; Huron people (Ohio) |
| 210 | Hutchinson County | 2 | |
| 210 | Hyde County | 2 | |
| 210 | Iowa County | 2 | |
| 210 | Jeff Davis County | 2 | Jefferson Davis |
| 210 | Johnston County | 2 | |
| 210 | Juneau County | 2 | |
| 210 | Kane County | 2 | |
| 210 | Kendall County | 2 | |
| 210 | King County | 2 | |
| 210 | Kings County | 2 | |
| 210 | Lane County | 2 | |
| 210 | Laurens County | 2 | Henry Laurens[4] and John Laurens[5] |
| 210 | Leon County | 2 | |
| 210 | Limestone County | 2 | |
| 210 | Louisa County | 2 | |
| 210 | Lucas County | 2 | |
| 210 | Marquette County | 2 | |
| 210 | McDowell County | 2 | |
| 210 | McHenry County | 2 | |
| 210 | Mecklenburg County | 2 | Charlotte of Mecklenburg-Strelitz |
| 210 | Medina County | 2 | Medina River (Texas) ; Medina, Saudi Arabia (Ohio) |
| 210 | Meigs County | 2 | Return J. Meigs Sr. |
| 210 | Menard County | 2 | |
| 210 | Menominee County | 2 | Menominee people |
| 210 | Midland County | 2 | |
| 210 | Mills County | 2 | |
| 210 | Mississippi County | 2 | Mississippi River |
| 210 | Morrow County | 2 | |
| 210 | Morton County | 2 | |
| 210 | Nassau County | 2 | |
| 210 | Nemaha County | 2 | |
| 210 | Nevada County | 2 | Nevada City (California); Nevada |
| 210 | Nicholas County | 2 | |
| 210 | Northumberland County | 2 | Northumberland, England |
| 210 | Oconee County | 2 | |
| 210 | Oldham County | 2 | |
| 210 | Otero County | 2 | |
| 210 | Otsego County | 2 | |
| 210 | Ouachita County | 2 | |
| 210 | Owen County | 2 | |
| 210 | Page County | 2 | |
| 210 | Panola County | 2 | |
| 210 | Paulding County | 2 | John Paulding |
| 210 | Pendleton County | 2 | Edmund Pendleton |
| 210 | Pennington County | 2 | |
| 210 | Perkins County | 2 | |
| 210 | Phelps County | 2 | |
| 210 | Plymouth County | 2 | Plymouth, Massachusetts |
| 210 | Pocahontas County | 2 | Pocahontas |
| 210 | Pontotoc County | 2 | Chickasaw word for the region |
| 210 | Portage County | 2 | Portages |
| 210 | Powell County | 2 | Lazarus Powell (Kentucky); John Wesley Powell (Montana) |
| 210 | Prairie County | 2 | Grand Prairie (Arkansas); Great Plains (Montana) |
| 210 | Quitman County | 2 | John A. Quitman |
| 210 | Ramsey County | 2 | Alexander Ramsey |
| 210 | Red River County | 2 | Red River |
| 210 | Renville County | 2 | Joseph Renville |
| 210 | Rice County | 2 | Samuel Rice (Kansas); Henry Rice (Minnesota) |
| 210 | Ripley County | 2 | Eleazer Wheelock Ripley |
| 210 | Roane County | 2 | |
| 210 | Roberts County | 2 | |
| 210 | Roosevelt County | 2 | Theodore Roosevelt |
| 210 | Rowan County | 2 | |
| 210 | Rush County | 2 | |
| 210 | Rusk County | 2 | |
| 210 | Rutherford County | 2 | Griffith Rutherford |
| 210 | Sabine County | 2 | Sabine River |
| 210 | San Miguel County | 2 | |
| 210 | Santa Cruz County | 2 | |
| 210 | Scotland County | 2 | Scotland |
| 210 | Sedgwick County | 2 | John Sedgwick |
| 210 | Seneca County | 2 | Seneca people |
| 210 | Seward County | 2 | William H. Seward |
| 210 | Shannon County | 2 | George Shannon; Peter Shannon |
| 210 | Sierra County | 2 | |
| 210 | Simpson County | 2 | |
| 210 | Spencer County | 2 | Spier Spencer |
| 210 | Stanley County | 2 | David Stanley |
| 210 | St. Charles County | 2 | Saint Charles Borromeo |
| 210 | St. Joseph County | 2 | St. Joseph River |
| 210 | St. Louis County | 2 | |
| 210 | Stafford County | 2 | |
| 210 | Stanton County | 2 | Edwin Stanton |
| 210 | Steele County | 2 | |
| 210 | Steuben County | 2 | Baron von Steuben |
| 210 | Stewart County | 2 | |
| 210 | Suffolk County | 2 | County of Suffolk in England |
| 210 | Sumner County | 2 | Edwin V. Sumner (Kansas); Jethro Sumner (Tennessee) |
| 210 | Surry County | 2 | County of Surrey in England |
| 210 | Talbot County | 2 | |
| 210 | Tazewell County | 2 | |
| 210 | Terrell County | 2 | |
| 210 | Texas County | 2 | The state of Texas |
| 210 | Thurston County | 2 | |
| 210 | Tioga County | 2 | |
| 210 | Tipton County | 2 | |
| 210 | Trinity County | 2 | Trinity River |
| 210 | Turner County | 2 | |
| 210 | Tyler County | 2 | John Tyler |
| 210 | Upshur County | 2 | Abel Parker Upshur |
| 210 | Wabash County | 2 | Wabash River |
| 210 | Walton County | 2 | |
| 210 | Walworth County | 2 | |
| 210 | Ward County | 2 | |
| 210 | Wells County | 2 | |
| 210 | Westmoreland County | 2 | County of Westmorland in England |
| 210 | Whitley County | 2 | William Whitley |
| 210 | Wichita County | 2 | Wichita people, indirectly |
| 210 | Wilcox County | 2 | |
| 210 | Wilkes County | 2 | John Wilkes |
| 210 | Wilkinson County | 2 | James Wilkinson |
| 210 | Williams County | 2 | |
| 210 | Windham County | 2 | Wineham [sic], England |
| 210 | Winston County | 2 | |
| 210 | Wise County | 2 | Henry Alexander Wise |
| 210 | Woodford County | 2 | William Woodford |
| 210 | Worcester County | 2 | |
| 210 | Yuma County | 2 | Yuma (Quechan) people |
