Md. Const. XI-A - Local Legislation § 2

The General Assembly shall by public general law provide a grant of express powers for such County or Counties as may thereafter form a charter under the provisions of this Article. Such express powers granted to the Counties and the powers heretofore granted to the City of Baltimore, as set forth in Article 4, Section 6, Public Local Laws of Maryland, shall not be enlarged or extended by any charter formed under the provisions of this Article, but such powers may be extended, modified, amended or repealed by the General Assembly.