Johnson County, IL Demographics
Johnson County, IL is the 79th most populous of 102 counties in Illinois, with 13,308 residents across 344 square miles. That is about 39 people per square mile.
At the 2020 census
| Population | 13,308 |
|---|---|
| Land area | 344 sq mi |
| Density | 39 / sq mi |
Data: 2020 Census · American Community Survey 2024
How Johnson 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: Johnson County, IL
Measured from the county's main population center using 2020 census blocks.
We're computing the drive-time and radius areas around Johnson County, IL — check back shortly. Meanwhile you can drop a pin anywhere in the radius tool.
Census tracts in Johnson County, IL
| Name | Population | Sq mi | Per sq mi |
|---|---|---|---|
| Census Tract 9776 | 4,332 | 149.0 | 29 |
| Census Tract 9778 | 3,462 | 120.5 | 29 |
| Census Tract 9777 | 3,067 | 73.0 | 42 |
| Census Tract 9800 | 2,447 | 1.4 | 1,812 |
Related places
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.