Maryland Code, Tax-Property § 13-407

(b)(1) Unless a greater rate of tax was imposed before July 1, 1979, a county may not impose county transfer tax on a transfer subject to the agricultural land transfer tax under Subtitle 3 of this title at a rate greater than the county rate applicable to the transfer of improved residential property in that county.

(2) If a county has imposed a county transfer tax at a rate that exceeds the rate applicable to the transfer of improved residential property, the total rate of tax that applies to a transfer subject to the agricultural land transfer tax may not exceed 5% plus the rate that applies to improved residential property under the county transfer tax.

(3) If the total rate of tax that applies to a transfer subject to the agricultural land transfer tax exceeds the maximum rate allowed under paragraph (2) of this subsection:

(1) impose a county transfer tax at a rate above the rate that was in effect on July 1, 1979; or

(2) increase the rate of a county transfer tax above the rate that was in effect on July 1, 1979.