County Founded
County Date Founded
#1 Ste. Genevieve County October 1st 1812
#1 Cape Girardeau County October 1st 1812
#1 New Madrid County October 1st 1812
#1 St. Charles County October 1st 1812
#1 St. Louis County October 1st 1812
#6 Washington County August 21st 1813
#7 Saint Louis City January 18th 1816
#8 Howard County Janurary 23rd 1816
#9 Franklin County October 11th 1818
#10 Jefferson County December 8th 1818
#10 Wayne County December 11th 1818
#11 Lincoln County December 14th 1818
#11 Madison County December 14th 1818
#11 Montgomery County December 14th 1818
#11 Pike County December 14th 1818
#15 Pulaski County December 15th 1818
#17 Cooper County December 17th 1818
#18 Boone County November 16th 1820
#18 CharitonCounty November 16th 1820
#18 Lafayette County November 16th 1820
#18 PerryCounty November 16th 1820
#18 Ralls County November 16th 1820
#18 Ray County November 16th 1820
#18 Atchison County November 16th 1820
#25 Cole County November 20th 1820
#26 Callaway County November 25th 1820
#26 Gasconade County November 25th 1820
#26 Saline County November 25th 1820
#29 Saint Francois County December 19th 1821
#30 Scott County December 28th 1821
#31 Clay County January 2nd 1822
#32 Marion County December 14th 1822
#33 Jackson County December 15th 1826
#34 Randolph County January 22nd 1829
#35 Crawford County January 23rd 1929
#36 Monroe County January 6th 1831
#37 Greene County January 2nd 1833
#37 Lewis County January 2nd 1833
#39 Benton County January 3rd 1833
#39 Carroll County January 3rd 1833
#41 Morgan County January 5th 1833
#41 Ripley County January 5th 1833
#41 Warren County January 5th 1833
#44 Clinton County January 15th 1833
#45 Pettis County January 26th 1833
#46 Johnson County December 13th 1834
#46 Henry County December 13th 1834
#48 Shelby County January 2nd 1835
#48 Stoddard County January 2nd 1835
#50 Cass County September 14th 1835
#51 Clark County January 2nd 1836
#52 BarryCounty January 5th 1836
#53 Audrain County December 17th 1836
#54 Caldwell County December 26th 1836
#55 Daviess County December 29th 1836
#56 Camden County January 6th 1837
#56 Livingston County January 6th 1837
#56 Macon County January 6th 1837
#59 Linn County January 7th 1837
#60 Taney County January 16th 1837
#61 Miller County February 6th 1837
#62 Polk County March 20th 1837
#63 Newton County December 31st 1838
#63 PlatteCounty December 31st 1838
#65 Buchanan County February 10th 1839
#66 AndrewCounty January 29th 1841
#66 Texas County January 29th 1841
#66 Adair County January 29th 1841
#66 Bates County January 29th 1841
#66 Dade County January 29th 1841
#66 Grundy County January 29th 1841
#66 Jasper County January 29th 1841
#66 Dallas County January 29th 1841
#66 Osage County January 29th 1841
#66 Scotland County January 29th 1841
#66 Shannon County January 29th 1841
#66 Wright County January 29th 1841
#78 Gentry County February 12th 1841
#79 St. Clair County February 15th 1841
#80 Sullivan County February 17th 1843
#81 Ozark County February 22nd 1843
#82 Holt County January 29th 1845
#83 Cedar County February 14th 1845
#83 Dunklin County February 14th 1845
#83 Harrison County February 14th 1845
#83 Hickory County February 14th 1845
#83 Knox County February 14th 1845
#83 Mercer County February 14th 1845
#83 Mississippi County February 14th 1845
#83 Moniteau County February 14th 1845
#83 Schuyler County February 14th 1845
#92 DeKalb County February 25th 1845
#92 Lawrence County February 25th 1845
#92 Reynolds County February 25th 1845
#95 Putnam County November 16th 1845
#96 Nodaway County December 14th 1845
#97 Butler County February 27th 1849
#97 Laclede County February 27th 1849
#99 McDonald County March 3rd 1849
#100 Dent County February 10th 1851
#100 Stone County February 10th 1851
#102 Pemiscot County February 15th 1851
#103 Vernon County February 17th 1851
#104 Bollinger County March 1st 1851
#105 Maries County March 2nd 1855
#106 Webster County March 3rd 1855
#107 Barton County December 12th 1855
#108 Iron County February 16th 1857
#109 Howell County March 2nd 1857
#110 Douglas County October 29th 1857
#111 Phelps County November 13th 1857
#112 Carter County March 13th 1859
#113 Christian County March 20th 1859
#114 Worth County February 8th 1861
#115 Oregon County February 14th 1845