Macau is about 6 times smaller than District of Columbia.

District of Columbia is approximately 177 sq km, while Macau is approximately 28 sq km, making Macau 15.93% the size of District of Columbia. Meanwhile, the population of District of Columbia is ~601,723 people (33,570 more people live in Macau).
Tip: This to-scale comparison of District of Columbia vs. Macau uses the Mercator projection, which distorts the size of regions near the poles.