Maryland Code, Transportation § 8-734

(a) If appropriate matching federal funds are available to this State under the federal Highway Beautification Act of 1965  1 and the Federal-Aid Highway Amendment of 1974,  2 the Administration shall acquire, by purchase, gift, or condemnation, and remove any outdoor sign that, on July 1, 1975, lawfully existed along or near any federal-aid primary highway and that does not comply with this part.

(b) In controlling outdoor signs adjacent to federal-aid primary highways under the federal Highway Beautification Act of 1965, the Federal-Aid Highway Amendment of 1974, and any related agreement between the Administration and the federal government, the Administration is not required to remove any sign that advertises a natural wonder or a scenic or historical attraction, if the sign conforms to national standards for such signs under Title 23 of the United States Code.