District of Columbia is about 7 times bigger than Tuvalu.

Tuvalu is approximately 26 sq km, while District of Columbia is approximately 177 sq km, making District of Columbia 581% larger than Tuvalu. Meanwhile, the population of Tuvalu is ~11,544 people (590,179 more people live in District of Columbia).
Tip: This to-scale comparison of Tuvalu vs. District of Columbia uses the Mercator projection, which distorts the size of regions near the poles.