Md. Const. art. IV, § 20

(a) There shall be a Circuit Court for each County and for Baltimore City. The Circuit Courts shall have and exercise, in the respective counties, and Baltimore City, all the power, authority and jurisdiction, original and appellate, which the Circuit Courts of the counties exercised on the effective date of these amendments, and the greater or lesser jurisdiction hereafter prescribed by law. (b) The judges of the Circuit Courts for Howard, Montgomery, and Harford Counties shall each, alternately and in rotation and on schedules to be established by those judges, sit as an Orphans’ Court for their County, and shall have and exercise all the power, authority and jurisdiction which the present Orphans’ Courts now have and exercise, or which may hereafter be provided by law.