D.C. Code § 3-305
The Armory Board shall set aside for the exclusive use of the District of Columbia National Guard such parts of the headquarters and regimental buildings and basement of the drill hall, and such of the storage rooms contiguous to the drill hall as shown upon drawing A-3, first-floor plan, approved by the Council of the District of Columbia April 19, 1940, as said Armory Board may from time to time find are necessary for the use of the National Guard. The parts of the Armory so set aside for the use of the National Guard shall be under the control and jurisdiction of the Commanding General of the National Guard for all purposes except maintenance and repair of the Armory. The drill hall and those parts of the Armory not set aside for the exclusive use of the National Guard shall be available to the National Guard under schedules for joint use made by the Armory Board so as to carry out the purposes and intent of this subchapter.
D.C. Code § 3-305