District of Columbia is about 2,855 times smaller than Spain.

Spain is approximately 505,370 sq km, while District of Columbia is approximately 177 sq km, making District of Columbia 0.04% the size of Spain. Meanwhile, the population of Spain is ~47.2 million people (46.6 million fewer people live in District of Columbia).
Tip: This to-scale comparison of Spain vs. District of Columbia uses the Mercator projection, which distorts the size of regions near the poles.