39 U.S. Code § 406. Postal services at Armed Forces installations

The Postal Service may establish branch post offices at camps, posts, bases, or stations of the Armed Forces and at defense or other strategic installations.
The Secretaries of Defense and Transportation shall make arrangements with the Postal Service to perform postal services through personnel designated by them at or through branch post offices established under subsection (a) of this section.
(Pub. L. 91–375, Aug. 12, 1970, 84 Stat. 724.)
Effective Date

Section effective July 1, 1971, pursuant to Resolution No. 71–9 of the Board of Governors. See section 15(a) of Pub. L. 91–375, set out as a note preceding section 101 of this title.