The Smithsonian Metro station is on the Orange and Blue lines. This is the only station that takes riders directly to the National Mall. However, if you're visiting a specific museum, check to see whether this station is the closest. For example, the Air and Space Museum is closest to the Federal Center stattion, and the National Gallery is closest to Archives-Navy Memorial.
Last train departs: Addison Road/New Carrollton- 12:09 a.m.
Franconia-Springfield/ Vienna-Fairfax- 12:01 a.m.
(Trains leave exactly 2 hours later on Friday and Saturday nights.)