District of Columbia is about 1.4 times smaller than Saint Pierre and Miquelon.

Saint Pierre and Miquelon is approximately 242 sq km, while District of Columbia is approximately 177 sq km, making District of Columbia 73.14% the size of Saint Pierre and Miquelon. Meanwhile, the population of Saint Pierre and Miquelon is ~5,257 people (596,466 more people live in District of Columbia).
Tip: This to-scale comparison of Saint Pierre and Miquelon vs. District of Columbia uses the Mercator projection, which distorts the size of regions near the poles.