Population of Counties in Missouri (2020)

In 2019, the most populous county in Missouri is St. Louis County with a population of 996,945. This represents modest population decline of 0.19% since the 2010 census. Other major counties in Missouri include Jackson County (700,307), St. Charles County (399,182), and St. Louis City (302,838). These are the only counties with more than 300,000 residents, although there are eight other counties with at least 100,000 residents. Of these counties, St. Charles County experienced the most rapid growth at 10.33% since 2010.

Missouri Counties with Fewest Residents

The smallest Missouri county in terms of population is Worth County with just 2,040 residents. This represents a growth rate of -5.20% since 2010. Missouri has six other counties under 5,000 residents including Mercer County (3,641), Knox County (3,947), and Holt County (4,404). All of these counties lost residents since 2010 with the most dramatic decline in Holt County with a growth rate of -10.40%.

Missouri Counties with Rapid Growth

The fastest-growing county in Missouri since the 2010 census is Platte County with a growth rate of 14.81%, bringing its total population to 102,985. Other counties with rapid growth include Clay County grew 10.63% to 246,365, and St. Charles County grew 10.33% to 399,182, and Boone County grew 10.30% to 180,005. The county with the most significant decline was Pemiscot County which lost 10.94% of its residents.

Name 2020 Population Growth Since 2010
St. Louis County996,945-0.19%
Jackson County700,3073.78%
St. Charles County399,18210.33%
St. Louis city302,838-5.16%
Greene County291,9236.04%
Clay County246,36510.63%
Jefferson County224,3472.39%
Boone County180,00510.30%
Jasper County120,6362.53%
Cass County104,9545.21%
Franklin County103,6702.19%
Platte County102,98514.81%
Buchanan County88,571-0.56%
Christian County86,98311.74%
Cape Girardeau County78,7533.76%
Cole County76,7960.85%
St. Francois County66,6921.77%
Newton County58,2660.15%
Lincoln County57,6869.46%
Taney County55,8527.59%
Johnson County53,6521.78%
Pulaski County52,014-1.58%
Camden County45,8153.94%
Callaway County44,8891.30%
Phelps County44,732-1.31%
Butler County42,639-0.35%
Pettis County42,5420.66%
Howell County40,076-1.20%
Webster County39,1097.85%
Scott County38,458-2.02%
Lawrence County38,359-0.60%
Barry County35,8860.92%
Laclede County35,7130.10%
Warren County34,7116.55%
Lafayette County32,598-2.35%
Polk County32,2013.33%
Stone County31,749-1.52%
Dunklin County29,423-7.89%
Stoddard County29,206-2.73%
Marion County28,592-0.67%
Texas County25,571-1.78%
Audrain County25,4730.09%
Adair County25,339-1.11%
Miller County25,3362.50%
Washington County24,943-1.00%
Randolph County24,763-2.71%
Crawford County23,957-2.67%
McDonald County23,078-0.00%
Saline County22,895-2.24%
Ray County22,883-2.60%
Nodaway County22,304-4.68%
Henry County21,792-2.02%
Vernon County20,528-2.97%
Clinton County20,470-1.30%
Morgan County20,358-0.89%
Benton County19,2780.96%
Perry County19,1501.12%
Pike County18,5040.14%
Wright County18,378-2.51%
Ste. Genevieve County17,888-1.38%
Andrew County17,6071.49%
Cooper County17,6030.00%
New Madrid County17,296-8.75%
Dallas County16,7620.23%
Bates County16,320-4.19%
Pemiscot County16,272-10.94%
Moniteau County16,1213.17%
Dent County15,441-1.67%
Macon County15,153-2.82%
Livingston County15,1460.13%
Gasconade County14,705-3.31%
Cedar County14,1651.40%
Osage County13,714-1.20%
Ripley County13,401-4.97%
Douglas County13,373-2.02%
Mississippi County13,336-6.82%
Wayne County13,122-2.85%
DeKalb County12,630-2.12%
Madison County12,188-0.12%
Bollinger County12,169-1.44%
Linn County12,037-5.68%
Barton County11,798-4.75%
Montgomery County11,534-5.59%
Oregon County10,541-3.62%
Ralls County10,2120.27%
Iron County10,177-4.05%
Howard County10,137-0.07%
Grundy County9,914-3.32%
Lewis County9,855-3.47%
Hickory County9,509-1.39%
St. Clair County9,395-4.37%
Caldwell County9,108-3.46%
Ozark County9,017-7.37%
Maries County8,769-4.57%
Carroll County8,743-5.82%
Monroe County8,664-1.34%
Harrison County8,414-6.13%
Daviess County8,313-1.64%
Shannon County8,189-3.05%
Dade County7,569-3.48%
Chariton County7,451-5.08%
Clark County6,842-4.11%
Gentry County6,628-1.81%
Reynolds County6,254-6.38%
Sullivan County6,221-7.66%
Carter County6,054-3.78%
Shelby County6,050-4.96%
Atchison County5,171-8.61%
Scotland County4,9662.60%
Putnam County4,757-4.36%
Schuyler County4,5993.56%
Holt County4,404-10.40%
Knox County3,947-4.32%
Mercer County3,641-3.42%
Worth County2,040-5.20%