Bordering states
Illinois vs Wisconsin
Short answer
- IL
- 12,710,158
- WI
- 5,960,975
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
Wisconsin
- < 24
- < 38
- < 60
- < 157
- ≥ 157
Side by side
| Measure | Illinois | Wisconsin |
|---|---|---|
| Residents, 2024 | 12,710,158 | 5,960,975 |
| Rank by population | 6th | 20th |
| Land, sq mi | 55,513 | 54,168 |
| People per sq mi | 229.0 | 110.0 |
| County-equivalents | 102 | 72 |
| Median county residents | 24,447 | 41,821 |
| Median county income | $65,901 | $70,174 |
| Most populous county | Cook County | Milwaukee County |
| Largest county by land | McLean County | Marathon County |
| Capital | Springfield | Madison |
| Daylight at capital, June 21 | 15 h 00 min | 15 h 22 min |
| Census division | East North Central | East North Central |
Population and density
Illinois has 12,710,158 residents, 2.1 times Wisconsin's 5,960,975. Illinois ranks 6th and Wisconsin 20th of the 50 states and DC. Illinois is the more crowded, with 229.0 people per square mile against 110.0, 2.1 times.
Land area
Illinois has 55,513 square miles of land, about the same as Wisconsin's 54,168. The largest county-equivalent in Illinois is McLean County at 1,183 square miles; in Wisconsin it is Marathon County at 1,545.
Counties
Illinois is divided into 102 county-equivalents and Wisconsin into 72, so an average Illinois county covers 544 square miles against 752. The typical county in Illinois has 24,447 residents, against 41,821 in Wisconsin. The most populous are Cook County (5,182,617) and Milwaukee County (924,740).
11 county names appear on both sides of the border: Adams, Brown, Clark, Crawford, Douglas, Jackson, Jefferson, Monroe, Richland, Washington, Winnebago. Use the FIPS code, not the name, when joining data across the two states.
Household income
The median county in Wisconsin has a household income of $70,174, 6% above Illinois's $65,901. The highest county incomes are Kendall County ($114,606) in Illinois and St. Croix County ($103,731) in Wisconsin, from SAIPE 2023.
Capitals and daylight
Springfield and Madison are 228 miles apart in a straight line; from Springfield the initial bearing is 3°, N. On June 21, 2026, Springfield gets 15 h 00 min of daylight and Madison 15 h 22 min; on December 21 the figures are 9 h 21 min and 9 h 00 min. Month by month tables are on the Springfield and Madison 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 Wisconsin 2.
Questions people ask
Which is bigger, Illinois or Wisconsin?
Illinois, with 55,513 square miles of land against 54,168, 1.02 times as large.
Which has more people, Illinois or Wisconsin?
Illinois has 12,710,158 residents, 2.1 times Wisconsin's 5,960,975.
How far is Springfield from Madison?
228 miles in a straight line, heading N (3°) from Springfield.
Do Illinois and Wisconsin have counties with the same name?
Yes, 11: Adams, Brown, Clark, Crawford, Douglas, Jackson, Jefferson, Monroe, Richland, Washington, Winnebago.
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.