For Wyoming, we refer you to the Wyoming State Statutes & Constitution, Title 6: Crimes and Offenses.
6-3-202. Altering landmarks; penalties.
(a) A person is guilty of altering landmarks if, with intent to destroy or deface the mark on a monument, landmark or bearing-tree designating the corner or boundary of a tract of land, he knowingly:
(i) Displaces the monument or landmark;
(ii) Defaces or alters the mark; or
(iii) Breaks, cuts down or removes the monument, landmark or bearing-tree.
(b) Altering landmarks is a misdemeanor punishable by imprisonment for not more than six (6) months, a fine of not more than seven hundred fifty dollars ($750.00), or both.
Furthermore, some survey monuments may be federally owned, such as the section corners for the U.S. Public Land Survey System (shown below). Those are actually stamped with the words “UNLAWFUL TO DISTURB.” Any unauthorized person who alters or removes of these government survey monuments could also be found guilty of a misdemeanor punishable with fines and/or imprisonment.
Wooden markers can be removed from your own property.