St Marks Episcopal Church is located at at 301 A St SE (map), just a block off Pennsylvania Ave SE and a few blocks walk from Union Station.
The most prominent part of the building is the Nave, or sanctuary. For BSFY events, enter through the A-Street courtyard. Use the door by the bike racks and take the stairs or elevator to the left of the entry way.  Classes are most typically in the dance studio on the second floor.  Camps are held on the basement level.
Strollers can be left in the lobby downstairs or brought up and stored outside of the studio door. Please remove shoes before entering the dance studio. Bathrooms are on the lobby and basement level.