Montana is about 6 times bigger than West Virginia.

West Virginia is approximately 62,361 sq km, while Montana is approximately 376,979 sq km, making Montana 505% larger than West Virginia. Meanwhile, the population of West Virginia is ~1.9 million people (863,579 fewer people live in Montana).
Tip: This to-scale comparison of West Virginia vs. Montana uses the Mercator projection, which distorts the size of regions near the poles.