Montana is about 23 times bigger than Hawaii.

Hawaii is approximately 16,635 sq km, while Montana is approximately 376,979 sq km, making Montana 2,166% larger than Hawaii. Meanwhile, the population of Hawaii is ~1.4 million people (370,886 fewer people live in Montana).
Tip: This to-scale comparison of Hawaii vs. Montana uses the Mercator projection, which distorts the size of regions near the poles.