Maryland Code, Labor and Employment § 4-505

(1) each charter county that engaged in collective bargaining with an employee organization prior to October 1, 1994;

(2) Charles County on or after October 1, 2017; and

(3) each municipal corporation that engages in collective bargaining with an employee organization prior to October 1, 1995.

(1) require any form of collective bargaining;

(2) require any method, means, or scope of bargaining between an employer and an exclusive representative; or

(3) authorize binding interest arbitration.