- Population: 5,595,211 (Change since 1990: +9.3%)
- Statehood: Aug. 10, 1821
- Capital city: Jefferson City
- Highest point: Taum Sauk Mountain, 1772 ft.
- Lowest point: Southwest tip of Bootheel, 230 ft.
- Bollinger County
- Population: 12,029 (Change since 1990: +13.3%)
- Created: March 1, 1851
- County seat: Marble Hill
- Largest town: Marble Hill (Pop. 1,502)
- Name origin: Col. George Frederick Bollinger
- Butler County
- Population: 40,867 (Change since 1990: +5.4%)
- Created: February 27, 1849
- County seat: Poplar Bluff
- Largest town: Poplar Bluff (Pop. 16,651)
- Name origin: Gen. William Orlando Butler
- Cape Girardeau County
- Population: 68,693 (Change since 1990: +11.5%)
- Created: October 1, 1812
- County seat: Jackson
- Largest town: Cape Girardeau (Pop. 35,349)
- Name origin: Ensign Jean B. Girardot
- Carter County
- Population: 5,941 (Change since 1990: +7.7%)
- Created: March 10, 1859
- County seat: Van Buren
- Largest town: Van Buren (Pop. 845)
- Name origin: Zimri A. Carter
- Crawford County
- Population: 22,804 (Change since 1990: +18.9%)
- Created: January 23, 1829
- County seat: Steelville
- Largest town: Cuba (Pop. 3,230)
- Name origin: William H. Crawford
- Dent County
- Population: 14,927 (Change since 1990: +8.9%)
- Created: February 10, 1851
- County seat: Salem
- Largest town: Salem (Pop. 4,854)
- Name origin: Lewis Dent
- Dunklin County
- Population: 33,155 (Change since 1990: +0.1%)
- Created: February 14, 1845
- County seat: Kennett
- Largest town: Kennett (Pop. 11,260)
- Name origin: Daniel Dunklin
- Franklin County
- Population: 93,807 (Change since 1990: +16.4%)
- Created: December 11, 1818
- County seat: Union
- Largest town: Washington (Pop. 13,243)
- Name origin: Benjamin Franklin
- Gasconade County
- Population: 15,342 (Change since 1990: +9.5%)
- Created: November 25, 1820
- County seat: Hermann
- Largest town: Hermann (Pop. 2,674)
- Howell County
- Population: 31,447 (1990 census)
- Created: March 2, 1857
- County seat: West Plains
- Largest town: West Plains (Pop. 10,866)
- Name origin: James Howell
- Iron County
- Population: 10,697 (Change since 1990: -0.3%)
- Created: February 17, 1857
- County seat: Ironton
- Largest town: Ironton (Pop. 1,471)
- Name origin: iron mining
- Jefferson County
- Population: 198,099 (Change since 1990: +15.6%)
- Created: December 8, 1818
- County seat: Hillsboro
- Largest town: Arnold (Pop. 19,965)
- Name origin: Thomas Jefferson
- Madison County
- Population: 11,800 (Change since 1990: +6.0%)
- Created: December 14, 1818
- County seat: Fredericktown
- Largest town: Fredericktown (Pop. 3,928)
- Name origin: James Madison
- Mississippi County
- Population: 13,427 (Change since 1990: -7.0%)
- Created: February 14, 1845
- County seat: Charleston
- Largest town: Charleston (Pop. 4,732)
- Name origin: Mississippi River
- New Madrid County
- Population: 19,760 (Change since 1990: -5.6%)
- Created: October 1, 1812
- County seat: New Madrid
- Largest town: New Madrid (Pop. 3,334)
- Name origin: New Madrid
- Oregon County
- Population: 10,344 (Change since 1990: +9.2%)
- Created: February 14, 1854
- County seat: Alton
- Largest town: Thayer (Pop. 2,201)
- Name origin: Territory of Oregon
- Pemiscot County
- Population: 20,047 (Change since 1990: -8.5%)
- Created: February 19, 1851
- County seat: Caruthersville
- Largest town: Caruthersville (Pop. 6,760)
- Name origin: "liquid mud"
- Perry County
- Population: 18,132 (Change since 1990: +8.9%)
- Created: November 16, 1820
- County seat: Perryville
- Largest town: Perryville (Pop. 7,667)
- Name origin: Oliver Perry
- Phelps County
- Population: 39,825 (Change since 1990: +13.0%)
- Created: November 13, 1857
- County seat: Rolla
- Largest town: Rolla (Pop. 16,367)
- Name origin: John F. Phelps
- Reynolds County
- Population: 6,689 (Change since 1990: +0.4%)
- Created: February 25, 1845
- County seat: Centerville
- Largest town: Ellington (Pop. 1,045)
- Name origin: Thomas Reynolds
- Ripley County
- Population: 13,509 (Change since 1990: +9.8%)
- Created: January 5, 1833
- County seat: Doniphan
- Largest town: Doniphan (Pop. 1,932)
- Name origin: Gen. Eleazer W. Ripley
- Scott County
- Population: 40,422 (Change since 1990: +2.7%)
- Created: December 28, 1821
- County seat: Benton
- Largest town: Sikeston (Pop. 16,992)
- Name origin: John Scott
- Shannon County
- Population: 8,324 (Change since 1990: +9.3%)
- Created: January 29, 1841
- County seat: Eminence
- Largest town: Winona (Pop. 1,290)
- Name origin: George Shannon
- St. Francois County
- Population: 55,641 (Change since 1990: +13.8%)
- Created: December 19, 1821
- County seat: Farmington
- Largest town: Farmington (Pop. 13,924)
- Name origin: St. Francis River
- St. Louis County
- Population: 1,016,315 (Change since 1990: +2.3%)
- Created: October 1, 1812
- County seat: Clayton
- Largest town: Florissant (Pop. 50,497)
- Name origin: City of St. Louis
- St. Louis
- Population: 348,189 (Change since 1990: -12.2%)
- Name origin: King Louis IX of France
- Ste. Genevieve County
- Population: 17,842 (Change since 1990: +11.3%)
- Created: October 1, 1812
- County seat: Ste. Genevieve
- Largest town: Ste. Genevieve (Pop. 4,476)
- Name origin: Sainte Genevieve
- Stoddard County
- Population: 29,705 (Change since 1990: +2.8%)
- Created: January 2, 1835
- County seat: Bloomfield
- Largest town: Dexter (Pop. 7,356)
- Name origin: Maj. Amos Stoddard
- Texas County
- Population: 23,003 (Change since 1990: +7.1%)
- Created: February 14, 1845
- County seat: Houston
- Largest town: Cabool (Pop. 2,168)
- Name origin: Republic of Texas
- Washington County
- Population: 23,344 (Change since 1990: +14.5%)
- Created: August 21, 1813
- County seat: Potosi
- Largest town: Potosi (Pop. 2,662)
- Name origin: George Washington
- Wayne County
- Population: 13,259 (Change since 1990: +14.9%)
- Created: December 11, 1818
- County seat: Greenville
- Largest town: Piedmont (Pop. 1,992)
- Name origin: Gen. Anthony Wayne
Timeline
- Apr. 9, 1682
- Robert Cavalier, Sieur de La Salle, claimed possession of Mississippi River valley for France. Named Louisiana after King Louis XIV.
- Nov. 13, 1762
- Spain took possession of Louisiana in Treaty of Fountainbleau
- Oct. 30, 1800
- France regained control of Louisiana
- Apr. 30, 1803
- Louisiana Purchased signed
- Mar. 3, 1805
- Louisiana Territory established with seat of government at St. Louis
- Jun. 4, 1812
- Missouri Territory divided from Louisiana
- Oct. 1, 1812
- First general assembly of Missouri Territory held. Five original counties (Cape Girardeau, New Madrid, St. Charles, St. Louis, and Ste. Genevieve) established.
- Jul. 19, 1820
- First Missouri Constitution adopted
- Aug. 10, 1821
- Missouri officially admitted as the 24th state
- Oct. 1, 1826
- Seat of government officially moved to Jefferson City
- Apr. 10, 1865
- Second Missouri Constitution adopted
- Oct. 30, 1875
- Third Missouri Constitution adopted
- Mar. 30, 1945
- Fourth and current Missouri Constitution enacted
| Year | Population | Percent change |
|---|
| 1820 | 66,586 | -- |
| 1830 | 140,455 | +110.9% |
| 1840 | 383,702 | +173.2% |
| 1850 | 682,038 | +77.8% |
| 1860 | 1,182,012 | +73.3% |
| 1870 | 1,721,295 | +45.6% |
| 1880 | 2,168,380 | +26.0% |
| 1890 | 2,679,204 | +23.6% |
| 1900 | 3,106,665 | +16.0% |
| 1910 | 3,293,335 | +6.0% |
| 1920 | 3,404,055 | +3.4% |
| 1930 | 3,629,367 | +6.6% |
| 1940 | 3,784,664 | +4.3% |
| 1950 | 3,954,653 | +4.5% |
| 1960 | 4,319,813 | +9.2% |
| 1970 | 4,677,623 | +8.3% |
| 1980 | 4,916,766 | +5.1% |
| 1990 | 5,117,073 | +4.1% |
| 2000 | 5,595,211 | +9.3% |