New Hampshire is around the same size as Belize.

Belize is approximately 22,966 sq km, while New Hampshire is approximately 23,227 sq km, making New Hampshire 1% larger than Belize. Meanwhile, the population of Belize is ~412,387 people (904,083 more people live in New Hampshire).
Tip: This to-scale comparison of Belize vs. New Hampshire uses the Mercator projection, which distorts the size of regions near the poles.