Montana is about 16 times bigger than New Hampshire.

New Hampshire is approximately 23,227 sq km, while Montana is approximately 376,979 sq km, making Montana 1,523% larger than New Hampshire. Meanwhile, the population of New Hampshire is ~1.3 million people (327,055 fewer people live in Montana).
Tip: This to-scale comparison of New Hampshire vs. Montana uses the Mercator projection, which distorts the size of regions near the poles.