# List of counties in Missouri

There are 114 counties and one independent city in the U.S. State of Missouri. Following the Louisiana Purchase and the admittance of Louisiana into the United States in 1812, five counties were formed out of the Missouri Territory at the first general assembly: Cape Girardeau, New Madrid, Saint Charles, Saint Louis, and Ste. Genevieve. Most subsequent counties were apportioned from these five original counties. Six more counties were added through the 1836 Platte Purchase, the acquired lands of which formed the northwest tip of the state and consisted of Andrew, Atchison, Buchanan, Holt, Nodaway, and Platte counties.
In Missouri, the county level of government comes between those of the city and the state. Its primary responsibilities include maintaining roads, providing security, prosecuting criminals, and collecting taxes. Elected officials at this level include a sheriff, prosecuting attorney, and assessor.
Most of the counties in Missouri are named after politicians. One such county, Cass, was originally named Van Buren County after President Martin Van Buren, and was changed to its present name in support of Van Buren's Democratic opponent Lewis Cass during the presidential election of 1848. Other counties are named after war heroes, natural resources, explorers, and former U.S. territories.
The city of St. Louis is an independent city, and is not within the limits of a county. Its residents voted to secede from St. Louis County in 1876. Throughout the United States, St. Louis is one of three independent cities outside the state of Virginia (the other two are Baltimore, Maryland, and Carson City, Nevada).
Population figures are based on the 2024 Census estimate. According to that census estimate, the population of Missouri is 6,245,466, an increase of 1.5% from 2020. The average population of Missouri's counties is 54,308; St. Louis County is the most populous (992,929), and Worth County is the least (1,872). The average land area is 599 sq mi (1,550 km$^2$). The largest county is Texas County (1,179 sq mi, 3,054 km$^2$) and the smallest is St. Louis city (61.9 sq mi, 160 km$^2$).
The Federal Information Processing Standard (FIPS) is used by the U.S. government to uniquely identify counties, and is provided for each entry. These codes link to the United States Census Bureau's "quick facts" for each county. To distinguish from counties in other states, one must use Missouri's FIPS code, 29. For example, Adair County's unique nationwide identifier is 29001.

## Counties

| County | FIPS code | County seat | Est. | Formed from | Etymology | Population | Area |
| Adair County | 001 | Kirksville | 1841 | Macon County | John Adair (1757–1840), pioneer, soldier, and seventh Governor of Kentucky | 25,660 | 568 sq mi (1,471 km$^2$) |
| Andrew County | 003 | Savannah | 1841 | Part of the Platte Purchase | Andrew Jackson Davis , a prominent citizen of St. Louis | 18,091 | 435 sq mi (1,127 km$^2$) |
| Atchison County | 005 | Rock Port | 1843 | Holt County, part of the Platte Purchase | U.S. Senator David Rice Atchison (1807–1886), a Democrat from Missouri | 5,139 | 545 sq mi (1,412 km$^2$) |
| Audrain County | 007 | Mexico | 1831 | Callaway, Monroe and Ralls counties | James Hunter Audrain, a War of 1812 colonel Missouri State Legislator | 24,304 | 693 sq mi (1,795 km$^2$) |
| Barry County | 009 | Cassville | 1835 | Greene County | William Taylor Barry (1784–1835), jurist and United States Postmaster General | 35,618 | 779 sq mi (2,018 km$^2$) |
| Barton County | 011 | Lamar | 1855 | Jasper County | U.S. Senator David Barton (1783–1837), one of the first senators from Missouri | 11,717 | 594 sq mi (1,538 km$^2$) |
| Bates County | 013 | Butler | 1841 | Van Buren (now Cass) County | Frederick Bates (1777–1825), the second governor of Missouri | 16,394 | 848 sq mi (2,196 km$^2$) |
| Benton County | 015 | Warsaw | 1835 | Pettis and Greene counties | Thomas Hart Benton (1782–1858), U.S. Senator from Missouri | 20,614 | 706 sq mi (1,829 km$^2$) |
| Bollinger County | 017 | Marble Hill | 1851 | Cape Girardeau, Madison, Stoddard and Wayne counties | George Frederick Bollinger (1770–1842), early settler of Missouri | 10,610 | 621 sq mi (1,608 km$^2$) |
| Boone County | 019 | Columbia | 1820 | Howard County | Daniel Boone (1734–1820), American pioneer and hunter | 192,154 | 685 sq mi (1,774 km$^2$) |
| Buchanan County | 021 | Saint Joseph | 1838 | Part of the Platte Purchase | James Buchanan (1791–1868), 15th President of the United States | 83,574 | 410 sq mi (1,062 km$^2$) |
| Butler County | 023 | Poplar Bluff | 1849 | Wayne County | William O. Butler (1791–1880), U.S. Representative from Kentucky and vice-presidential nominee under Lewis Cass | 41,814 | 698 sq mi (1,808 km$^2$) |
| Caldwell County | 025 | Kingston | 1836 | Ray County | Disputed; either John Caldwell, an Indian scout and friend of respected Colonel Alexander William Doniphan; John Caldwell, Lieutenant Governor of Kentucky; or Mathew Caldwell, a signer of the Texas Declaration of Independence | 9,000 | 429 sq mi (1,111 km$^2$) |
| Callaway County | 027 | Fulton | 1821 | Boone, Howard and Montgomery counties | James Callaway (1783–1815), soldier during the War of 1812 and grandson of Daniel Boone | 45,126 | 839 sq mi (2,173 km$^2$) |
| Camden County | 029 | Camdenton | 1841 | Benton, Morgan and Pulaski counties | Charles Pratt, 1st Earl Camden (1714–1794), an English lawyer, judge, Whig politician, and proponent of civil liberties | 44,135 | 655 sq mi (1,696 km$^2$) |
| Cape Girardeau County | 031 | Jackson | 1812 | One of the five original counties | A rock promontory over the Mississippi River and Ensign Sieur Jean Baptiste de Girardot, a French officer and early explorer of the region | 83,658 | 579 sq mi (1,500 km$^2$) |
| Carroll County | 033 | Carrollton | 1833 | Ray County | Charles Carroll (1737–1832), delegate to the Continental Congress and U.S. Senator for Maryland | 8,414 | 695 sq mi (1,800 km$^2$) |
| Carter County | 035 | Van Buren | 1859 | Oregon, Reynolds, Ripley and Shannon counties | Zimri Carter (1794-1872), a pioneering settler | 5,359 | 508 sq mi (1,316 km$^2$) |
| Cass County | 037 | Harrisonville | 1833 | Jackson County | Lewis Cass (1782–1866), senator from Michigan | 113,873 | 699 sq mi (1,810 km$^2$) |
| Cedar County | 039 | Stockton | 1845 | Dade and St. Clair counties | Named for the abundance of Eastern Red Cedar trees | 15,023 | 476 sq mi (1,233 km$^2$) |
| Chariton County | 041 | Keytesville | 1821 | Howard County | Chariton River, a tributary of the Missouri River, whose naming origin is disputed | 7,397 | 756 sq mi (1,958 km$^2$) |
| Christian County | 043 | Ozark | 1859 | Greene, Taney and Webster counties | William Christian (1743–1786), colonel in the American Revolution | 96,045 | 563 sq mi (1,458 km$^2$) |
| Clark County | 045 | Kahoka | 1836 | Lewis County | William Clark (1770–1838), American explorer, soldier, Indian agent, and territorial governor | 6,623 | 507 sq mi (1,313 km$^2$) |
| Clay County | 047 | Liberty | 1822 | Ray County | Henry Clay (1777–1852), American Senator and orator from Kentucky | 263,370 | 396 sq mi (1,026 km$^2$) |
| Clinton County | 049 | Plattsburg | 1833 | Clay County | George Clinton (1739–1812), soldier and Governor of New York, considered one of the Founding Fathers of the United States | 21,721 | 419 sq mi (1,085 km$^2$) |
| Cole County | 051 | Jefferson City | 1820 | Cooper County | Stephen Cole, pioneering settler | 77,625 | 392 sq mi (1,015 km$^2$) |
| Cooper County | 053 | Boonville | 1818 | Howard County | Sarshel Benjamin Cooper, pioneering settler | 17,122 | 565 sq mi (1,463 km$^2$) |
| Crawford County | 055 | Steelville | 1829 | Gasconade County | William H. Crawford (1772–1834), U.S. Senator from Georgia, U.S. Secretary of Treasury, and judge | 22,808 | 743 sq mi (1,924 km$^2$) |
| Dade County | 057 | Greenfield | 1841 | Barry and Polk counties | Major Francis L. Dade (1793?–1835), Major in the U.S. 4th Infantry Regiment, United States Army, during the Second Seminole War | 7,622 | 490 sq mi (1,269 km$^2$) |
| Dallas County | 059 | Buffalo | 1841 | Polk County | George M. Dallas (1792–1864), U.S. Vice President under James K. Polk | 17,877 | 542 sq mi (1,404 km$^2$) |
| Daviess County | 061 | Gallatin | 1836 | Ray County | Joseph Hamilton Daveiss (1774–1811), commanded the Dragoons of the Indiana Militia at the Battle of Tippecanoe | 8,541 | 567 sq mi (1,469 km$^2$) |
| DeKalb County | 063 | Maysville | 1843 | Clinton County | Johann de Kalb (1721–1780), a German soldier who served as a major general in the Continental Army during the American Revolutionary War | 9,884 | 424 sq mi (1,098 km$^2$) |
| Dent County | 065 | Salem | 1851 | Crawford and Shannon counties | James Dent, pioneering settler | 14,721 | 754 sq mi (1,953 km$^2$) |
| Douglas County | 067 | Ava | 1857 | Ozark County | Stephen A. Douglas (1813–1861), American Senator from Illinois, and the Democratic nominee for President in 1860 | 12,290 | 815 sq mi (2,111 km$^2$) |
| Dunklin County | 069 | Kennett | 1843 | Stoddard County | Daniel Dunklin (1790–1844), fifth governor of Missouri | 27,002 | 546 sq mi (1,414 km$^2$) |
| Franklin County | 071 | Union | 1818 | St. Louis County | Benjamin Franklin (1706–1790), writer, publisher, orator, and one of the Founding Fathers of the United States | 107,256 | 922 sq mi (2,388 km$^2$) |
| Gasconade County | 073 | Hermann | 1821 | Franklin County | Gasconade River, a tributary of the Missouri River; the river probably derives its name from the French word "gascon" which means braggart, and could be an old satirical name describing those who boast about their adventures upon return to St. Louis | 14,655 | 520 sq mi (1,347 km$^2$) |
| Gentry County | 075 | Albany | 1841 | Clinton County | Richard Gentry (1788–1837), a distinguished American military colonel in the Seminole Wars | 6,298 | 492 sq mi (1,274 km$^2$) |
| Greene County | 077 | Springfield | 1833 | Crawford and Wayne counties | Nathanael Greene (1742–1786), a major general of the Continental Army in the American Revolutionary War | 307,942 | 675 sq mi (1,748 km$^2$) |
| Grundy County | 079 | Trenton | 1839 | Livingston County | Felix Grundy (1777–1840), U.S. Congressman and U.S. Senator from Tennessee who also served as the 13th Attorney General of the United States | 9,766 | 436 sq mi (1,129 km$^2$) |
| Harrison County | 081 | Bethany | 1843 | Daviess County | Albert G. Harrison (1800–1839), U.S. Representative from Missouri | 8,186 | 725 sq mi (1,878 km$^2$) |
| Henry County | 083 | Clinton | 1834 | Lillard (now Lafayette) County | Patrick Henry (1736–1799), first post-colonial Governor of Virginia and prominent figure in the American Revolution | 22,575 | 702 sq mi (1,818 km$^2$) |
| Hickory County | 085 | Hermitage | 1845 | Benton and Polk counties | Andrew Jackson (1767–1845), seventh U.S. President, who was nicknamed "Old Hickory" during his military service | 8,766 | 399 sq mi (1,033 km$^2$) |
| Holt County | 087 | Oregon | 1841 | Part of the Platte Purchase | David Rice Holt, Missouri State Representative | 4,241 | 462 sq mi (1,197 km$^2$) |
| Howard County | 089 | Fayette | 1816 | St. Charles and St. Louis counties | Benjamin Howard (1760–1814), a Congressman from Kentucky, governor of Missouri Territory and a brigadier general in the War of 1812 | 10,150 | 466 sq mi (1,207 km$^2$) |
| Howell County | 091 | West Plains | 1857 | Oregon County | Disputed – Josiah Howell, pioneering settler | 40,762 | 928 sq mi (2,404 km$^2$) |
| Iron County | 093 | Ironton | 1857 | Madison, Reynolds, St. Francois, Washington and Wayne counties | The abundance of iron ore in the area | 9,420 | 551 sq mi (1,427 km$^2$) |
| Jackson County | 095 | Independence, Kansas City | 1826 | Lillard (now Lafayette) County | Andrew Jackson (1767–1845), U.S. Senator from Tennessee and later 7th President of the United States from 1829 to 1837 | 727,362 | 605 sq mi (1,567 km$^2$) |
| Jasper County | 097 | Carthage | 1841 | Barry County | William Jasper (c. 1750–1779), a noted American soldier in the Revolutionary War | 126,479 | 640 sq mi (1,658 km$^2$) |
| Jefferson County | 099 | Hillsboro | 1818 | St. Louis and Sainte Genevieve counties | Thomas Jefferson (1743–1826), third President of the United States, principal author of the Declaration of Independence, and one of the most influential Founding Fathers | 231,888 | 657 sq mi (1,702 km$^2$) |
| Johnson County | 101 | Warrensburg | 1834 | Lillard (now Lafayette) County | Richard M. Johnson (1780–1850), ninth Vice President of the United States, serving in the administration of Martin Van Buren | 55,880 | 831 sq mi (2,152 km$^2$) |
| Knox County | 103 | Edina | 1843 | Scotland County | Henry Knox (1750–1806) an American bookseller from Boston who became the chief artillery officer of the Continental Army and later the nation's first Secretary of War | 3,740 | 506 sq mi (1,311 km$^2$) |
| Laclede County | 105 | Lebanon | 1849 | Camden, Pulaski and Wright counties | Pierre Laclede (1729–1778), founder of St. Louis, Missouri | 36,738 | 766 sq mi (1,984 km$^2$) |
| Lafayette County | 107 | Lexington | 1821 | Cooper County | Gilbert du Motier, the Marquis de Lafayette (1757–1834), French military officer and general in the American Revolutionary War | 33,511 | 629 sq mi (1,629 km$^2$) |
| Lawrence County | 109 | Mount Vernon | 1843 | Barry and Dade counties | James Lawrence (1781–1813), an American naval officer best known for his last words "Don't give up the ship!" | 39,151 | 613 sq mi (1,588 km$^2$) |
| Lewis County | 111 | Monticello | 1833 | Marion County | Meriwether Lewis (1774–1809), explorer and governor of the Louisiana Territory | 9,852 | 505 sq mi (1,308 km$^2$) |
| Lincoln County | 113 | Troy | 1818 | St. Charles County | Disputed; either Lincoln County, Kentucky (birthplace of Christopher Clark, a Missouri legislator who advocated for the county's creation), or for Benjamin Lincoln (1733–1810), an American revolutionary war general | 65,888 | 630 sq mi (1,632 km$^2$) |
| Linn County | 115 | Linneus | 1837 | Chariton County | Lewis F. Linn (1796–1843), a Jacksonian Democratic U.S. Senator for Missouri | 11,910 | 620 sq mi (1,606 km$^2$) |
| Livingston County | 117 | Chillicothe | 1837 | Carroll County | Edward Livingston (1764–1836), a prominent American jurist and statesman, influential in the drafting of the Louisiana Civil Code of 1825, a civil code based largely on the Napoleonic Code | 14,658 | 535 sq mi (1,386 km$^2$) |
| Macon County | 121 | Macon | 1837 | Chariton and Randolph counties | Nathaniel Macon (1758–1837), member of the United States House of Representatives from 1791 to 1815 who briefly served in the American Revolutionary War | 15,177 | 804 sq mi (2,082 km$^2$) |
| Madison County | 123 | Fredericktown | 1818 | Cape Girardeau and Sainte Genevieve counties | James Madison (1751–1836), politician and political philosopher who served as the fourth President of the United States, and one of the Founding Fathers of the United States | 12,852 | 497 sq mi (1,287 km$^2$) |
| Maries County | 125 | Vienna | 1855 | Osage and Pulaski counties | Maries River, possibly a corruption of the French word marais meaning "marsh" or "swamp" | 8,506 | 528 sq mi (1,368 km$^2$) |
| Marion County | 127 | Palmyra | 1826 | Ralls County | Francis Marion (1732–1795), a military officer who served in the American Revolutionary War | 28,425 | 438 sq mi (1,134 km$^2$) |
| McDonald County | 119 | Pineville | 1847 | Newton County | Alexander McDonald, American Revolutionary War sergeant | 24,054 | 540 sq mi (1,399 km$^2$) |
| Mercer County | 129 | Princeton | 1845 | Grundy County | John F. Mercer (1759–1821), an American lawyer, planter, and Governor of Maryland | 3,452 | 454 sq mi (1,176 km$^2$) |
| Miller County | 131 | Tuscumbia | 1837 | Cole and Pulaski counties | John Miller (1781–1846), an American publisher and politician from St. Louis, Missouri. He was the fourth Governor of Missouri and represented Missouri in the U.S. House | 25,668 | 592 sq mi (1,533 km$^2$) |
| Mississippi County | 133 | Charleston | 1842 | Scott County | Mississippi River, the second-longest river in the United States which forms Missouri's eastern border | 11,750 | 413 sq mi (1,070 km$^2$) |
| Moniteau County | 135 | California | 1845 | Cole and Morgan counties | Moniteau Creek; "moniteau" is a French spelling of manitou, the Algonquian Great Spirit | 15,294 | 417 sq mi (1,080 km$^2$) |
| Monroe County | 137 | Paris | 1831 | Ralls County | James Monroe (1758–1831), fifth President of the United States who crafted the Missouri Compromise | 8,890 | 646 sq mi (1,673 km$^2$) |
| Montgomery County | 139 | Montgomery City | 1818 | St. Charles County | Richard Montgomery (1738–1775), an Irish-born soldier who first served in the British Army and later became a brigadier-general in the Continental Army during the Revolutionary War | 11,511 | 539 sq mi (1,396 km$^2$) |
| Morgan County | 141 | Versailles | 1833 | Cooper County | Daniel Morgan (c. 1736–1802), American pioneer, soldier, and United States Representative from Virginia | 22,399 | 598 sq mi (1,549 km$^2$) |
| New Madrid County | 143 | New Madrid | 1812 | One of the five original counties | Madrid, Spain | 15,212 | 678 sq mi (1,756 km$^2$) |
| Newton County | 145 | Neosho | 1838 | Barry County | John Newton (1755–1780), legendary soldier of the American Revolution | 61,519 | 626 sq mi (1,621 km$^2$) |
| Nodaway County | 147 | Maryville | 1843 | Andrew County, the Platte Purchase | Nodaway River, a 120-mile (190 km) long river in southwest Iowa and northwest Missouri | 20,503 | 877 sq mi (2,271 km$^2$) |
| Oregon County | 149 | Alton | 1841 | Ripley County | Oregon Territory | 8,699 | 792 sq mi (2,051 km$^2$) |
| Osage County | 151 | Linn | 1841 | Gasconade County | Osage River, a 360 miles (580 km) long tributary of the Missouri River in central Missouri; the name of the river is probably derived from a French corruption of "Washazhe" – the name of the Osage Native Americans | 13,478 | 606 sq mi (1,570 km$^2$) |
| Ozark County | 153 | Gainesville | 1841 | Taney County | Ozark Mountains – Ozark is the anglicized form of the French "aux arcs", an abbreviation of "Aux Arkansas", which means in the county of Arkansas | 9,090 | 747 sq mi (1,935 km$^2$) |
| Pemiscot County | 155 | Caruthersville | 1851 | New Madrid County | An American Indian word meaning "liquid mud" | 14,407 | 493 sq mi (1,277 km$^2$) |
| Perry County | 157 | Perryville | 1821 | Sainte Genevieve County | Oliver Hazard Perry (1785–1819), naval officer in the War of 1812 against Britain, earned the title "Hero of Lake Erie" for leading American forces in a decisive naval victory at the Battle of Lake Erie | 19,100 | 475 sq mi (1,230 km$^2$) |
| Pettis County | 159 | Sedalia | 1833 | Cooper and Saline counties | Spencer Darwin Pettis (1802–1831), U.S. Representative from Missouri | 43,791 | 685 sq mi (1,774 km$^2$) |
| Phelps County | 161 | Rolla | 1857 | Crawford County | John S. Phelps (1814–1886), a politician, soldier during the American Civil War, and twenty-third Governor of Missouri | 45,672 | 673 sq mi (1,743 km$^2$) |
| Pike County | 163 | Bowling Green | 1818 | St. Charles County | Zebulon Pike (1778–1813), American soldier and explorer for whom Pikes Peak in Colorado is also named | 17,961 | 673 sq mi (1,743 km$^2$) |
| Platte County | 165 | Platte City | 1838 | Part of the Platte Purchase | Platte River, a tributary of the Missouri River, which is in turn named for the French word "platte" meaning flat or shallow | 113,207 | 420 sq mi (1,088 km$^2$) |
| Polk County | 167 | Bolivar | 1835 | Greene County | James K. Polk (1795–1849), 11th President of the United States | 33,070 | 637 sq mi (1,650 km$^2$) |
| Pulaski County | 169 | Waynesville | 1833 | Crawford County | Kazimierz Pulaski (1745–1779), Polish soldier of fortune in the American Revolutionary War, he saved the life of George Washington and became a general in the Continental Army | 53,964 | 547 sq mi (1,417 km$^2$) |
| Putnam County | 171 | Unionville | 1843 | Adair and Sullivan counties | Israel Putnam (1718–1790), an American army general who fought with distinction at the Battle of Bunker Hill during the American Revolutionary War | 4,539 | 518 sq mi (1,342 km$^2$) |
| Ralls County | 173 | New London | 1821 | Pike County | Daniel Ralls, a Missouri State Representative | 10,499 | 471 sq mi (1,220 km$^2$) |
| Randolph County | 175 | Huntsville | 1829 | Chariton and Ralls counties | John Randolph of Roanoke (1773–1833), a leader in Congress from Virginia and spokesman for the "Old Republican" | 24,077 | 482 sq mi (1,248 km$^2$) |
| Ray County | 177 | Richmond | 1820 | Howard County | John Ray, Missouri State Representative | 23,199 | 570 sq mi (1,476 km$^2$) |
| Reynolds County | 179 | Centerville | 1845 | Shannon County | Thomas Reynolds (1796–1844), governor of Missouri from 1840 to 1844 | 5,927 | 811 sq mi (2,100 km$^2$) |
| Ripley County | 181 | Doniphan | 1831 | Wayne County | Eleazer Wheelock Ripley (1782–1839), Brigadier General in the War of 1812 | 10,715 | 630 sq mi (1,632 km$^2$) |
| Saint Charles County | 183 | Saint Charles | 1812 | One of the five original counties | St. Charles Borromeo (1538–1584), an Italian saint and cardinal of the Roman Catholic Church | 423,726 | 561 sq mi (1,453 km$^2$) |
| Saint Clair County | 185 | Osceola | 1841 | Rives (now Henry) County | Arthur St. Clair (1737–1818), an American soldier and Governor of the Northwest Territory | 9,848 | 677 sq mi (1,753 km$^2$) |
| Saint Francois County | 187 | Farmington | 1821 | Jefferson, Ste. Genevieve and Washington counties | St. Francis of Assisi (c. 1182–1226), a Catholic deacon and the founder of the Order of Friars Minor, more commonly known as the Franciscans | 67,503 | 450 sq mi (1,165 km$^2$) |
| Saint Louis County | 189 | Clayton | 1812 | One of the five original counties | King Louis IX (1214–1270), King of France from 1226 until his death | 992,929 | 508 sq mi (1,316 km$^2$) |
| Saint Louis City | 510 | St. Louis | 1876 | Created in 1876 when city residents voted to secede from St. Louis County | King Louis IX (1214–1270), King of France from 1226 until his death | 279,695 | 61.9 sq mi (160 km$^2$) |
| Sainte Genevieve County | 186 | Ste. Genevieve | 1812 | One of the five original counties | St. Genevieve (c. 420 – c. 510), the patron saint of Paris in Roman Catholic and Eastern Orthodox tradition | 18,546 | 502 sq mi (1,300 km$^2$) |
| Saline County | 195 | Marshall | 1820 | Cooper County | Local hot springs | 23,325 | 756 sq mi (1,958 km$^2$) |
| Schuyler County | 197 | Lancaster | 1843 | Adair County | Philip Schuyler (1733–1804), a general in the American Revolution and a United States Senator from New York | 4,069 | 308 sq mi (798 km$^2$) |
| Scotland County | 199 | Memphis | 1841 | Clark, Lewis, and Shelby counties | Scotland (country) | 4,698 | 438 sq mi (1,134 km$^2$) |
| Scott County | 201 | Benton | 1822 | New Madrid County | John Guier Scott (1819–1892), a U.S. Representative from Missouri | 37,957 | 421 sq mi (1,090 km$^2$) |
| Shannon County | 203 | Eminence | 1837 | Ripley County | George Shannon (1785–1836), member of the Lewis and Clark Expedition | 7,275 | 1,004 sq mi (2,600 km$^2$) |
| Shelby County | 205 | Shelbyville | 1835 | Marion County | Isaac Shelby (1750–1826), the first and fifth Governor of Kentucky | 5,926 | 501 sq mi (1,298 km$^2$) |
| Stoddard County | 207 | Bloomfield | 1835 | New Madrid County | Amos Stoddard (1762–1813), the only commandant of Upper Louisiana for the French Republic and the only commandant for the District of Louisiana for the United States in 1804 during the handover of the Louisiana Purchase | 28,438 | 827 sq mi (2,142 km$^2$) |
| Stone County | 209 | Galena | 1851 | Taney County | William Stone, first elected judge of Taney County | 32,630 | 463 sq mi (1,199 km$^2$) |
| Sullivan County | 211 | Milan | 1843 | Linn County | John Sullivan (1740–1795), American Revolutionary War general | 5,750 | 651 sq mi (1,686 km$^2$) |
| Taney County | 213 | Forsyth | 1837 | Greene County | Roger Brooke Taney (1777–1864), eleventh United States Attorney General and fifth Chief Justice of the United States | 56,744 | 632 sq mi (1,637 km$^2$) |
| Texas County | 215 | Houston | 1843 | Shannon and Wright counties | Republic of Texas | 25,715 | 1,179 sq mi (3,054 km$^2$) |
| Vernon County | 217 | Nevada | 1851 | Bates County | Miles Vernon, Missouri State Senator – the county was originally defined as having the same boundaries as Bates county, but was later declared unconstitutional and changed | 19,787 | 834 sq mi (2,160 km$^2$) |
| Warren County | 219 | Warrenton | 1833 | Montgomery County | Joseph Warren (1741–1775), Revolutionary War doctor and general | 38,478 | 432 sq mi (1,119 km$^2$) |
| Washington County | 221 | Potosi | 1813 | Sainte Genevieve County | George Washington (1732–1799), commander of the Continental Army in the American Revolutionary War and first President of the United States | 23,583 | 760 sq mi (1,968 km$^2$) |
| Wayne County | 223 | Greenville | 1818 | Cape Girardeau and Lawrence counties | Anthony Wayne (1745–1796), United States Army general and statesman | 10,820 | 761 sq mi (1,971 km$^2$) |
| Webster County | 225 | Marshfield | 1855 | Greene County | Daniel Webster (1782–1852), U.S. Secretary of State and Senator from Massachusetts | 42,041 | 593 sq mi (1,536 km$^2$) |
| Worth County | 227 | Grant City | 1861 | Gentry County | William J. Worth (1794–1849), a United States general during the Mexican–American War | 1,872 | 266 sq mi (689 km$^2$) |
| Wright County | 229 | Hartville | 1841 | Pulaski County | Silas Wright (1795–1847), an American Democratic politician and Governor of New York | 19,505 | 682 sq mi (1,766 km$^2$) |

## Former county names

| County | Etymology | Changed to |
| Allen County | Unknown | Atchison County in 1845 |
| Ashley County | William Henry Ashley (1778–1838), early settler | Texas County in 1845 upon organization |
| Decatur County | Stephen Decatur (1779–1820), American naval officer | Ozark County in 1845 |
| Highland County | Unknown | Sullivan County in 1845 upon organization |
| Kinderhook County | Kinderhook, New York, birthplace of Martin Van Buren | Camden County in 1843 |
| Lillard County | James Lillard of Tennessee, who served in the first state legislature of Missouri | Lafayette County in 1825 |
| Niangua County | Niangua River, a tributary of the Osage River – "niangua" comes from the Native American word nehemgar, which means "a river of numerous springs or sources" | Dallas County in 1844 because of the difficulty in pronouncing and spelling Niangua |
| Seneca County | Seneca Nation, a group of Native Americans from New York | McDonald County in 1847 upon organization |
| Van Buren County | Martin Van Buren (1782–1862), eighth President of the United States and also Vice President under Andrew Jackson | Cass County in 1849 in honor of Van Buren's opponent in the presidential election of 1848 |