Md. Code, Transportation § 8–727

(a) Except as otherwise provided in this section, this part regulates the erection and maintenance of an outdoor sign along or near a federal-aid primary highway, only if:

(1) The sign is wholly or partly visible from the main traveled way of the highway; and

(2) The sign is:

(i) 660 feet or less from the nearest edge of the right-of-way of the highway; or

(ii) More than 660 feet from the nearest edge of the right-of-way of the highway, and intended to be read from the main traveled way of the highway.

(b) Except as provided in §§ 8-734 and 8-735 of this subtitle as to the removal of nonconforming signs, this part does not apply to:

(1) An outdoor sign that is 660 feet or less from the nearest edge of a federal-aid primary highway, if the sign was erected on or before July 1, 1968; or

(2) An outdoor sign that is more than 660 feet from the nearest edge of a federal-aid primary highway, if the sign was erected on or before July 1, 1975.

(c) This part does not apply to on premise outdoor signs.