District of Columbia Code
Chapter 2 - United States Park Police
§ 5–208. Environs of the District of Columbia defined

For the purposes of §§ 5-206 to 5-208, the environs of the District of Columbia are hereby defined as embracing Arlington, Fairfax, Loudoun, Prince William, and Stafford Counties and the City of Alexandria in Virginia, and Prince George’s, Charles, Anne Arundel, and Montgomery Counties in Maryland.
(Mar. 17, 1948, 62 Stat. 81, ch. 136, § 3; Aug. 18, 1970, 84 Stat. 826, Pub. L. 91-383, § 4.)
1981 Ed., § 4-208.
1973 Ed., § 4-211.