Jefferson County, IL Demographics
Jefferson County, IL is the 37th most populous of 102 counties in Illinois, with 37,113 residents across 571 square miles. That is about 65 people per square mile.
At the 2020 census
| Population | 37,113 |
|---|---|
| Land area | 571 sq mi |
| Density | 65 / sq mi |
Data: 2020 Census · American Community Survey 2024
How Jefferson 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: Jefferson County, IL
Measured from the county's main population center using 2020 census blocks.
We're computing the drive-time and radius areas around Jefferson County, IL — check back shortly. Meanwhile you can drop a pin anywhere in the radius tool.
Census tracts in Jefferson County, IL
| Name | Population | Sq mi | Per sq mi |
|---|---|---|---|
| Census Tract 504 | 4,733 | 117.2 | 40 |
| Census Tract 503 | 4,243 | 162.8 | 26 |
| Census Tract 508 | 4,155 | 32.1 | 129 |
| Census Tract 501 | 4,142 | 108.3 | 38 |
| Census Tract 505 | 3,724 | 27.8 | 134 |
| Census Tract 507 | 3,669 | 9.2 | 398 |
| Census Tract 506 | 3,084 | 4.7 | 659 |
| Census Tract 502 | 3,077 | 94.9 | 32 |
| Census Tract 511 | 2,579 | 12.6 | 204 |
| Census Tract 509 | 2,351 | 0.7 | 3,146 |
| Census Tract 510 | 1,356 | 0.8 | 1,705 |
Related places
Other counties nearby
Nearest counties
Metro areas containing Jefferson County
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.