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St. Louis County, MO Demographics

St. Louis County, MO is the most populous of 115 counties in Missouri, with 1,004,111 residents across 508 square miles. That is about 1,977 people per square mile.

At the 2020 census

Population 1,004,111
Land area 508 sq mi
Density 1,977 / sq mi

Data: 2020 Census · American Community Survey 2024

How St. Louis County compares to the US

We're computing this county's comparison table — check back shortly. Population, land area, and density above are already exact.

Central Location: St. Louis County, MO

Measured from the county's main population center using 2020 census blocks.

We're computing the drive-time and radius areas around St. Louis County, MO — check back shortly. Meanwhile you can drop a pin anywhere in the radius tool.

Census tracts in St. Louis County, MO

Name Population Sq mi Per sq mi
Census Tract 2177.02 7,813 5.0 1,572
Census Tract 2215.03 7,682 15.9 484
Census Tract 2176 7,577 4.6 1,649
Census Tract 2214.21 7,476 17.6 425
Census Tract 2215.02 7,476 21.1 355
Census Tract 2178.02 7,426 2.4 3,089
Census Tract 2109.12 7,155 7.0 1,017
Census Tract 2216.25 7,131 2.2 3,289
Census Tract 2179.23 7,103 2.0 3,615
Census Tract 2163 7,068 0.8 9,339
Census Tract 2111.01 7,056 1.3 5,431
Census Tract 2132.02 7,012 2.1 3,372
Census Tract 2206.01 6,746 2.3 2,895
Census Tract 2178.52 6,729 2.7 2,533
Census Tract 2147 6,721 1.3 5,250
Census Tract 2216.27 6,677 6.3 1,068
Census Tract 2152.01 6,657 4.5 1,490
Census Tract 2106 6,645 2.6 2,544
Census Tract 2178.07 6,462 1.8 3,525
Census Tract 2113.01 6,432 1.2 5,295
Census Tract 2205.01 6,421 1.2 5,374
Census Tract 2179.31 6,366 1.5 4,331
Census Tract 2194 6,335 1.5 4,136
Census Tract 2113.32 6,293 1.3 5,025
Census Tract 2212.02 6,219 4.0 1,556
Census Tract 2188 6,176 1.3 4,763
Census Tract 2108.06 6,151 1.9 3,167
Census Tract 2199 6,101 1.0 5,847
Census Tract 2108.05 6,080 1.9 3,170
Census Tract 2113.31 6,067 1.1 5,645
Census Tract 2204.41 6,024 1.4 4,243
Census Tract 2179.41 6,016 1.8 3,283
Census Tract 2107.02 5,984 1.9 3,145
Census Tract 2216.26 5,953 5.3 1,130
Census Tract 2150.05 5,941 1.0 5,699
Census Tract 2197 5,887 1.7 3,439
Census Tract 2213.35 5,855 3.7 1,588
Census Tract 2116 5,855 1.5 3,788
Census Tract 2179.44 5,818 1.5 3,819
Census Tract 2180.13 5,814 1.7 3,423
Census Tract 2108.07 5,760 2.5 2,321
Census Tract 2206.02 5,760 1.6 3,522
Census Tract 2216.31 5,721 2.0 2,881
Census Tract 2202 5,704 1.4 4,216
Census Tract 2214.25 5,688 1.5 3,800
Census Tract 2157 5,681 1.4 4,059
Census Tract 2151.44 5,672 2.2 2,546
Census Tract 2208.01 5,657 1.8 3,165
Census Tract 2216.29 5,600 12.1 463
Census Tract 2178.06 5,595 2.1 2,663
Census Tract 2175 5,587 5.1 1,090
Census Tract 2102 5,576 1.7 3,342
Census Tract 2154 5,507 4.3 1,289
Census Tract 2148 5,481 1.2 4,524
Census Tract 2177.01 5,425 5.6 962
Census Tract 2109.25 5,419 1.3 4,209
Census Tract 2179.42 5,402 1.3 4,006
Census Tract 2109.23 5,399 0.9 5,984
Census Tract 2112.01 5,337 1.5 3,469
Census Tract 2114.01 5,325 9.5 558
Census Tract 2221 5,298 8.5 623
Census Tract 2178.41 5,280 1.6 3,286
Census Tract 2165 5,279 0.9 5,923
Census Tract 2155 5,260 2.0 2,569
Census Tract 2152.33 5,234 2.6 2,018
Census Tract 2135 5,222 1.1 4,611
Census Tract 2204.48 5,197 1.1 4,728
Census Tract 2204.49 5,189 2.2 2,402
Census Tract 2179.32 5,144 1.7 2,984
Census Tract 2200.01 5,090 0.9 5,861
Census Tract 2208.02 5,073 1.3 3,882
Census Tract 2185 5,064 1.1 4,413
Census Tract 2184.02 5,054 1.4 3,710
Census Tract 2156 5,042 2.8 1,795
Census Tract 2178.53 5,015 1.6 3,071
Census Tract 2132.03 5,014 2.1 2,422
Census Tract 2215.06 5,003 1.3 3,802
Census Tract 2111.02 5,002 1.6 3,195
Census Tract 2151.02 4,979 1.5 3,374
Census Tract 2180.12 4,955 2.1 2,342
Census Tract 2204.45 4,940 2.9 1,685
Census Tract 2113.33 4,918 2.1 2,324
Census Tract 2174 4,915 0.8 6,434
Census Tract 2151.45 4,914 1.3 3,918
Census Tract 2214.24 4,912 1.7 2,909
Census Tract 2108.03 4,898 1.6 3,091
Census Tract 2208.03 4,897 1.7 2,841
Census Tract 2179.21 4,833 7.5 645
Census Tract 2144 4,789 1.1 4,244
Census Tract 2195.01 4,764 1.1 4,435
Census Tract 2152.31 4,751 1.8 2,659
Census Tract 2138 4,720 0.9 5,094
Census Tract 2153.01 4,689 2.5 1,874
Census Tract 2109.27 4,681 8.8 530
Census Tract 2134.01 4,644 1.2 3,948
Census Tract 2213.32 4,642 1.9 2,434
Census Tract 2123 4,623 1.0 4,714
Census Tract 2152.35 4,612 1.5 3,086
Census Tract 2125 4,599 1.1 4,312
Census Tract 2216.21 4,512 24.3 185

Showing the 100 most populous of 236 — the rest are shown on the map.

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About this page

This page shows demographics for a US county from the 2020 census and the American Community Survey: population, land area, density, urban share, and how the county compares to national averages for income, housing, age, and more.

Counties subdivide into census tracts, listed below with their populations. The drive-time and radius tables measure the population around the county's main population center.

Read how BlockAtlas computes population within an area →