18 U.S.C. § 1164

Whoever willfully destroys, defaces, or removes any sign erected by an Indian tribe, or a Government agency (1) to indicate the boundary of an Indian reservation or of any Indian country as defined in section 1151 of this title or (2) to give notice that hunting, trapping, or fishing is not permitted thereon without lawful authority or permission, shall be fined under this title or imprisoned not more than six months, or both.