The District of Columbia is that portion of the territory of the United States ceded by the State of Maryland for the permanent seat of government of the United States, including the river Potomac in its course through the District, and the islands therein.
D.C. Code § 1-101
Territorial area
R.S., D.C., § 1; June 11, 1878, 20 Stat. 102, ch. 180, § 1
Official source: D.C. Law Library (Council of the District of Columbia). Reproduced from public-domain District of Columbia statutes; confirm against the official source for the current text. Not legal advice.