Bordering states
Illinois vs Indiana
Short answer
- IL
- 12,710,158
- IN
- 6,924,275
The two states, county by county
Both maps share one density scale, so the same shade means the same number of people per square mile on either side of the border. Darker counties are denser. Select a county to open its page.
Illinois
Indiana
- < 34
- < 53
- < 79
- < 174
- ≥ 174
Side by side
| Measure | Illinois | Indiana |
|---|---|---|
| Residents, 2024 | 12,710,158 | 6,924,275 |
| Rank by population | 6th | 17th |
| Land, sq mi | 55,513 | 35,825 |
| People per sq mi | 229.0 | 193.3 |
| County-equivalents | 102 | 92 |
| Median county residents | 24,447 | 34,874 |
| Median county income | $65,901 | $66,685 |
| Most populous county | Cook County | Marion County |
| Largest county by land | McLean County | Allen County |
| Capital | Springfield | Indianapolis |
| Daylight at capital, June 21 | 15 h 00 min | 15 h 00 min |
| Census division | East North Central | East North Central |
Population and density
Illinois has 12,710,158 residents, 84% more than Indiana's 6,924,275. Illinois ranks 6th and Indiana 17th of the 50 states and DC. Illinois is the more crowded, with 229.0 people per square mile against 193.3, 18% more.
Land area
Illinois has 55,513 square miles of land, 55% more than Indiana's 35,825. The largest county-equivalent in Illinois is McLean County at 1,183 square miles; in Indiana it is Allen County at 657.
Counties
Illinois is divided into 102 county-equivalents and Indiana into 92, so an average Illinois county covers 544 square miles against 389. The typical county in Illinois has 24,447 residents, against 34,874 in Indiana. The most populous are Cook County (5,182,617) and Marion County (981,628).
43 county names appear on both sides of the border: Adams, Boone, Brown, Carroll, Cass, Clark, Clay, Clinton, Crawford, DeKalb, Fayette, Franklin, Fulton, Greene, Hamilton, Hancock, Henry, Jackson, Jasper, Jefferson, Johnson, Knox, Lake, Lawrence, Madison, Marion, Marshall, Monroe, Montgomery, Morgan, Perry, Pike, Pulaski, Putnam, Randolph, Scott, Shelby, Union, Wabash, Warren, Washington, Wayne, White. Use the FIPS code, not the name, when joining data across the two states.
Household income
The typical county household income is about the same in both: $65,901 in Illinois and $66,685 in Indiana. The highest county incomes are Kendall County ($114,606) in Illinois and Hamilton County ($121,231) in Indiana, from SAIPE 2023.
Capitals and daylight
Springfield and Indianapolis are 185 miles apart in a straight line; from Springfield the initial bearing is 89°, E. On June 21, 2026, Springfield gets 15 h 00 min of daylight and Indianapolis 15 h 00 min; on December 21 the figures are 9 h 21 min and 9 h 21 min. Month by month tables are on the Springfield and Indianapolis daylight pages.
Where they sit
Both are in the Census East North Central division of the Midwest region. By county internal points, Illinois spans 2 UTM zones and Indiana 1.
Questions people ask
Which is bigger, Illinois or Indiana?
Illinois, with 55,513 square miles of land against 35,825, 1.55 times as large.
Which has more people, Illinois or Indiana?
Illinois has 12,710,158 residents, 84% more than Indiana's 6,924,275.
How far is Springfield from Indianapolis?
185 miles in a straight line, heading E (89°) from Springfield.
Do Illinois and Indiana have counties with the same name?
Yes, 43: Adams, Boone, Brown, Carroll, Cass, Clark, Clay, Clinton, Crawford, DeKalb, Fayette, Franklin, Fulton, Greene, Hamilton, Hancock, Henry, Jackson, Jasper, Jefferson, Johnson, Knox, Lake, Lawrence, Madison, Marion, Marshall, Monroe, Montgomery, Morgan, Perry, Pike, Pulaski, Putnam, Randolph, Scott, Shelby, Union, Wabash, Warren, Washington, Wayne, White.
Sources and data as of
Data as of: Census Vintage 2024 population estimates, 2024 Gazetteer land area and internal points, SAIPE 2023 median household income.
- 01Census Vintage 2024 county population estimates
- 02Census 2024 Gazetteer, counties
- 03Census SAIPE 2023 state and county estimates
- 04Census Bureau regions and divisions of the United States (last verified 2026-09-30)
How every number is computed: methodology. Spotted a wrong figure? Report an error.