State size comparison
compared to
Montana is about 2.6 times bigger than Illinois.
Illinois is approximately 143,961 sq km, while Montana is approximately 376,979 sq km, making Montana 162% larger than Illinois. Meanwhile, the population of Illinois is ~12.8 million people (11.8 million fewer people live in Montana).
Compare further: Montana vs. Illinois
Flip Comparison · See true size
See Montana on top of Illinois
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Quality of Life Comparison · 14 statistics
Make 33.5% more money in Illinois
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Cost of Living Comparison · 7 categories - 2026 data
Illinois is 0.6% more expensive than Montana
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City Size Comparison · See true size
Compare the size of Los Angeles vs Chicago
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