D.C. Code § 10-801.01

For the purposes of this subchapter, the term “real property” means land titled in the name of the District of Columbia (“District”) or in which the District has a controlling interest and includes all structures of a permanent character erected thereon or affixed thereto, any natural resources located thereon or thereunder, all riparian rights attached thereto, or any air space located above or below the property or any street or alley under the jurisdiction of the Mayor.