Guam is about 3.1 times bigger than District of Columbia.

District of Columbia is approximately 177 sq km, while Guam is approximately 544 sq km, making Guam 207% larger than District of Columbia. Meanwhile, the population of District of Columbia is ~601,723 people (432,637 fewer people live in Guam).
Tip: This to-scale comparison of District of Columbia vs. Guam uses the Mercator projection, which distorts the size of regions near the poles.