Quick search by citation:

16 U.S. Code § 446 - Sites for tablets at Antietam; care and supervision

All lands acquired by the United States, whether by purchase, gift, or otherwise, for the purposes of sites for tablets for the marking of the lines of battle of the Army of the Potomac and of the Army of Northern Virginia at Antietam, and of the position of each of the forty-three different commands of the Regular Army engaged in the battle of Antietam, shall be under the care and supervision of the Secretary of the Interior.

(Aug. 30, 1890, ch. 837, § 1, 26 Stat. 401; Ex. Ord. No. 6166, § 2, June 10, 1933; Ex. Ord. No. 6228, § 1, July 28, 1933.)
Executive Documents
Transfer of Functions

Administrative functions of certain national military parks transferred to Department of the Interior by Ex. Ord. Nos. 6166 and 6228, set out in notes under section 901 of Title 5, Government Organization and Employees.

National Park Service substituted for Office of National Parks, Buildings, and Reservations referred to in Ex. Ord. No. 6166, by act Mar. 2, 1934, ch. 38, § 1, 48 Stat. 389.