Ohio is about 1.4 times smaller than Illinois.

Illinois is approximately 143,961 sq km, while Ohio is approximately 106,056 sq km, making Ohio 73.67% the size of Illinois. Meanwhile, the population of Illinois is ~12.8 million people (1.3 million fewer people live in Ohio).
This to-scale comparison of Illinois vs. Ohio uses the Mercator projection, which distorts the size of regions near the poles. Learn more.

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