Museum Station, or Smithsonian Station, is part of the Metro system under the Capital Wasteland. It's under The Mall and gives an underground passage between the Museum of History and the Museum of Technology. It was originally part of the Red Line.
The station is part of a long underground network which goes from the collapsed car tunnel at the back of the GNR building plaza all the way down to the Anacostia Crossing Station at Rivet City. The station is filled with a few raiders – who are attempting to clear a radroach infestation in the upper mezzanine, as well as one or two super mutants.
The name of this station, where it is identified as Smithsonian, appeared on an advertisement for the Metro.
Museum station appears only in Fallout 3.