Population of Counties in Missouri (2021)

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 2021 Population Growth Since 2010 Density (mi²)
St. Louis County992,177-0.67%1,428.27
Jackson County707,4654.83%1,018.42
St. Charles County408,50612.91%588.06
Greene County297,1507.93%427.76
St. Louis City294,890-7.66%424.50
Clay County257,12415.48%370.14
Jefferson County226,4233.33%325.94
Boone County183,26712.29%263.82
Jasper County123,0744.60%177.17
Cass County107,8028.07%155.18
Platte County107,72620.09%155.08
Franklin County104,4693.00%150.39
Christian County91,69717.80%132.00
Buchanan County85,766-3.71%123.46
Cape Girardeau County79,3374.53%114.21
Cole County76,7950.85%110.55
St. Francois County68,1714.03%98.13
Lincoln County61,81317.35%88.98
Newton County58,3920.37%84.06
Taney County56,3468.56%81.11
Johnson County54,9444.29%79.09
Pulaski County53,8271.83%77.49
Camden County47,0896.83%67.79
Phelps County44,617-1.49%64.23
Callaway County44,3210.02%63.80
Butler County42,260-1.23%60.83
Pettis County42,135-0.33%60.65
Webster County40,41811.28%58.18
Howell County40,099-1.12%57.72
Lawrence County38,537-0.14%55.48
Scott County37,758-3.83%54.35
Warren County37,41514.75%53.86
Laclede County35,9770.78%51.79
Barry County35,9431.09%51.74
Lafayette County33,040-1.02%47.56
Stone County32,4540.68%46.72
Polk County32,0192.77%46.09
Stoddard County28,547-4.93%41.09
Marion County28,510-0.96%41.04
Dunklin County28,437-11.00%40.94
Miller County26,2276.11%37.75
Audrain County25,318-0.53%36.45
Texas County25,182-3.30%36.25
Adair County25,077-2.14%36.10
Randolph County24,780-2.66%35.67
Washington County24,324-3.48%35.02
Crawford County23,824-3.27%34.30
Ray County23,164-1.50%33.35
McDonald County22,585-2.11%32.51
Saline County22,503-3.92%32.39
Henry County21,856-1.83%31.46
Nodaway County21,830-6.71%31.43
Morgan County21,0532.48%30.31
Vernon County20,705-2.15%29.81
Clinton County20,291-2.16%29.21
Benton County19,7353.35%28.41
Perry County18,860-0.41%27.15
Wright County18,493-1.52%26.62
Ste. Genevieve County17,928-1.10%25.81
Pike County17,902-3.11%25.77
Cooper County17,8751.55%25.73
Andrew County17,8122.70%25.64
Dallas County17,0702.08%24.57
New Madrid County16,684-11.88%24.02
Moniteau County16,0242.55%23.07
Bates County15,908-6.58%22.90
Dent County15,625-0.73%22.49
Livingston County15,3191.26%22.05
Macon County15,017-3.69%21.62
Pemiscot County14,903-18.39%21.45
Cedar County14,7755.77%21.27
Gasconade County14,758-2.92%21.24
Osage County13,541-2.62%19.49
Ripley County13,024-7.64%18.75
Douglas County12,837-5.96%18.48
Mississippi County12,752-11.01%18.36
DeKalb County12,611-2.20%18.15
Wayne County12,355-8.61%17.79
Bollinger County12,021-2.60%17.30
Madison County11,888-2.53%17.11
Linn County11,682-8.55%16.82
Barton County11,682-5.66%16.82
Montgomery County11,677-4.34%16.81
Oregon County10,471-4.24%15.07
Ralls County10,4592.61%15.06
Iron County10,001-5.58%14.40
Howard County9,885-2.52%14.23
Hickory County9,7160.73%13.99
Lewis County9,650-5.48%13.89
Grundy County9,600-6.37%13.82
St. Clair County9,413-4.17%13.55
Ozark County9,382-3.73%13.51
Caldwell County8,918-5.41%12.84
Monroe County8,660-1.43%12.47
Carroll County8,585-7.51%12.36
Maries County8,551-6.67%12.31
Harrison County8,268-7.80%11.90
Daviess County8,166-3.35%11.76
Shannon County8,120-3.83%11.69
Dade County7,555-3.62%10.88
Chariton County7,364-5.96%10.60
Clark County6,725-5.75%9.68
Gentry County6,517-3.45%9.38
Reynolds County6,246-6.44%8.99
Sullivan County5,801-13.89%8.35
Shelby County5,796-8.94%8.34
Carter County5,780-8.17%8.32
Atchison County5,063-10.48%7.29
Scotland County4,830-0.21%6.95
Schuyler County4,7927.90%6.90
Putnam County4,592-7.68%6.61
Holt County4,385-10.78%6.31
Knox County3,947-4.32%5.68
Mercer County3,599-4.54%5.18
Worth County1,987-7.67%2.86