State size comparison

compared to

Illinois is about 1.2 times smaller than Oklahoma.

Oklahoma is approximately 177,847 sq km, while Illinois is approximately 143,961 sq km, making Illinois 80.95% the size of Oklahoma. Meanwhile, the population of Oklahoma is ~3.8 million people (9.1 million more people live in Illinois).
Tip: This to-scale comparison of Oklahoma vs. Illinois uses the Mercator projection, which distorts the size of regions near the poles.
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Compare further: Illinois vs. Oklahoma
Flip Comparison · See true size
See Illinois on top of Oklahoma
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Cost of Living Comparison · 7 categories - 2026 data
Oklahoma is 5.8% cheaper than Illinois
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