Sao Tome and Principe is about 5 times bigger than District of Columbia.

District of Columbia is approximately 177 sq km, while Sao Tome and Principe is approximately 964 sq km, making Sao Tome and Principe 445% larger than District of Columbia. Meanwhile, the population of District of Columbia is ~601,723 people (384,559 fewer people live in Sao Tome and Principe).
Tip: This to-scale comparison of District of Columbia vs. Sao Tome and Principe uses the Mercator projection, which distorts the size of regions near the poles.