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Franklin County, IL Demographics

Franklin County, IL is the 35th most populous of 102 counties in Illinois, with 37,804 residents across 409 square miles. That is about 92 people per square mile.

At the 2020 census

Population 37,804
Land area 409 sq mi
Density 92 / sq mi

Data: 2020 Census · American Community Survey 2024

How Franklin 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: Franklin County, IL

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

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

Census tracts in Franklin County, IL

Name Population Sq mi Per sq mi
Census Tract 407 4,370 21.4 204
Census Tract 412 3,644 137.2 27
Census Tract 404 3,636 42.1 86
Census Tract 411 3,298 6.9 476
Census Tract 408 3,259 61.1 53
Census Tract 405 3,053 29.4 104
Census Tract 403 3,046 6.6 458
Census Tract 401 3,025 38.3 79
Census Tract 402 2,979 54.5 55
Census Tract 406 2,640 6.4 410
Census Tract 410 2,541 1.7 1,503
Census Tract 409 2,313 3.3 704

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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 →