South Korea is about 2.1 times smaller than Idaho.

Idaho is approximately 214,314 sq km, while South Korea is approximately 99,720 sq km, making South Korea 46.53% the size of Idaho. Meanwhile, the population of Idaho is ~1.6 million people (50.3 million more people live in South Korea).
Tip: This to-scale comparison of Idaho vs. South Korea uses the Mercator projection, which distorts the size of regions near the poles.
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