Maine is about 2.2 times smaller than North Dakota.

North Dakota is approximately 178,647 sq km, while Maine is approximately 79,931 sq km, making Maine 44.74% the size of North Dakota. Meanwhile, the population of North Dakota is ~672,591 people (655,770 more people live in Maine).
Tip: This to-scale comparison of North Dakota vs. Maine uses the Mercator projection, which distorts the size of regions near the poles.