Dupont Circle Station

 is part of the Metro system under the Capital Wasteland. It is mainly collapsed and you have to go through a Raider-infested cave to get to Metro Central.

Notable Loot
Lying, Congressional Style is in the room with the Protectron, on a desk in a bin, next to the door

Trivia
In real life, Dupont Circle does not have a subway station (yet).