The map above shows Illinois and Ohio side by side at exactly the same scale, using equal-area projections, so their true relative sizes are preserved.
Illinois vs Ohio Geography
Land area
- Illinois has a land area of 55,513 square miles (143,778 km²), while Ohio has 40,859 square miles (105,824 km²).
- Illinois' land area is 1.4 times (36%) larger than Ohio's.
Total area
- Illinois: 57,913 square miles (149,995 km²) vs Ohio: 44,826 square miles (116,098 km²), including inland and coastal water.
- Illinois' total area is 1.3 times (29%) larger than Ohio's.
Length
- Illinois is 390 miles (628 km) long from north to south; Ohio is 291 miles (468 km).
- Illinois' north-south length is 1.3 times (34%) longer than Ohio's.
Width
- Illinois spans 283 miles (456 km) east to west; Ohio spans 317 miles (510 km).
- Ohio's east-west width is 1.1 times (12%) wider than Illinois'.
Highest point
- Illinois's highest point is Charles Mound at 1,232 feet (376 m); Ohio's is Campbell Hill at 1,547 feet (472 m).
- Campbell Hill is 315 feet higher than Charles Mound.
Lowest point
- Illinois's lowest point is Mississippi River at 292 feet; Ohio's is Ohio River at 455 feet.
- Illinois's lowest point is 163 feet lower.
Illinois vs Ohio Population and History
Population
- Illinois has a population of 12,710,158 (2024), while Ohio has 11,883,304 (2024).
- Illinois' population is 1.1 times (7%) larger than Ohio's.
Population density
- Illinois: 229.0 people per square mile vs Ohio: 290.8.
- Ohio's population density is 1.3 times (27%) higher than Illinois'.
Biggest city
- Illinois's biggest city is Chicago with 2,721,308 people; Ohio's is Columbus with 933,263.
- Chicago's population is 2.9 times (192%) larger than Columbus'.
Largest metro area
- Illinois's largest metropolitan area is Chicago-Naperville-Elgin, IL-IN metro area (9,408,576 people) vs Ohio's Cincinnati, OH-KY-IN metro area (2,302,815).
- Chicago-Naperville-Elgin, IL-IN metro area's population is 4.1 times (309%) larger than Cincinnati, OH-KY-IN metro area's.
History
- Illinois: Admitted to the Union on December 3, 1818, as the 21st state.
- Ohio: Admitted to the Union on March 1, 1803, as the 17th state.
- In its current form, Ohio is the older of the two by 15 years.
Illinois vs Ohio Economy
GDP
- Illinois's GDP is $1,148.1 billion (2024) vs Ohio's $923.1 billion.
- Illinois' economic output is 1.2 times (24%) larger than Ohio's.
GDP per capita
- Illinois: $90,330 per person vs Ohio: $77,684.
- Illinois' GDP per capita is 1.2 times (16%) higher than Ohio's.
Average income
- Illinois: $74,522 vs Ohio: $64,464 average income per person (per capita personal income).
- Illinois' average income is 1.2 times (16%) higher than Ohio's.
Illinois vs Ohio Counties
Number of counties
- Illinois has 102 counties, while Ohio has 88.
- Illinois' county count is 1.2 times (16%) higher than Ohio's.
Biggest county by area
- Illinois's largest county is McLean County at 1,183 square miles; Ohio's is Ashtabula County at 702 square miles.
- McLean County's land area is 1.7 times (68%) larger than Ashtabula County's.
Smallest county by area
- Illinois: Putnam County (160 sq mi) vs Ohio: Lake County (229 sq mi).
- Lake County's land area is 1.4 times (43%) larger than Putnam County's.
Most populous county
- Illinois: Cook County (5,182,617 people) vs Ohio: Franklin County (1,356,303 people).
- Cook County's population is 3.8 times (282%) larger than Franklin County's.
Least populous county
- Illinois: Hardin County (3,550 people) vs Ohio: Vinton County (12,545 people).
- Vinton County's population is 3.5 times (253%) larger than Hardin County's.
Richest county
- Illinois: Cumberland County ($104,890 per capita income) vs Ohio: Delaware County ($96,573).
- Cumberland County's income is 1.1 times (9%) richer than Delaware County's.
Poorest county
- Illinois: Lawrence County ($43,606 per capita income) vs Ohio: Noble County ($34,940).
- Lawrence County's income is 1.2 times (25%) richer than Noble County's.
Illinois vs Ohio Taxes
State income tax
- Illinois has a top income tax rate of 4.95%, while Ohio has a top income tax rate of 2.75%.
- Illinois's top rate is 2.2 percentage points higher.
Property tax
- Illinois: 1.92% effective rate vs Ohio: 1.22% of home value per year.
- Illinois's rate is 0.7 percentage points higher.
Sales tax
- Illinois: 8.98% combined state and average local rate vs Ohio: 7.29%.
- Illinois's combined rate is 1.69 percentage points higher.
Official Websites
Illinois official website · Ohio official website
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More Size Comparisons
All Illinois size comparisons · All Ohio size comparisons
Area, elevation and boundary figures come from official national statistics and US Census Bureau and Natural Earth boundary data; US state population, economic, county and tax figures come from the US Census Bureau, the Bureau of Economic Analysis and the Tax Foundation. Figures are rounded and for general reference.