Montana is about 1.5 times bigger than Guinea.

Guinea is approximately 245,857 sq km, while Montana is approximately 376,979 sq km, making Montana 53% larger than Guinea. Meanwhile, the population of Guinea is ~13.2 million people (12.2 million fewer people live in Montana).
Tip: This to-scale comparison of Guinea vs. Montana uses the Mercator projection, which distorts the size of regions near the poles.
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