8 U.S.C. § 930 : US Code - Section 930: Possession of firearms and dangerous weapons in Federal facilities
(a) Except as provided in subsection (d)[cops, military duty-carry, etc], whoever
knowingly possesses or causes to be present a firearm or other dangerous
weapon in a Federal facility (other than a Federal court facility), or attempts
to do so, shall be fined under this title or imprisoned not more than 1 year, or both.