Md. Code, Local Government § 4–416

(a) (1) Notwithstanding § 4–104(f) of this title, if an area is annexed to a

municipality that has planning and zoning authority at the time of annexation, the

municipality shall have exclusive jurisdiction over planning, subdivision control, and

zoning in the area annexed.

(2) Paragraph (1) of this subsection does not grant any planning or

zoning power or subdivision control to a municipality that is not authorized to

exercise planning or zoning power or subdivision control at the time of annexation.

(b) Without the express approval of the county commissioners or county

council of the county in which the municipality is located, for 5 years after an

annexation by a municipality, the municipality may not allow development of the

annexed land for land uses substantially different than the authorized use, or at a

substantially higher density, not exceeding 50%, than could be granted for the

proposed development, in accordance with the zoning classification of the county

applicable at the time of the annexation.

(c) Notwithstanding § 4–204 of the Land Use Article and if the county

expressly approves, the municipality may place the annexed land in a zoning

classification that allows a land use or density different from the land use or density

specified in the zoning classification of the county or agency with planning and zoning

jurisdiction over the land prior to its annexation applicable at the time of the

annexation.