To affiliate with a party or to change your party affiliation, you can designate your preference by using Maryland?s online voter registration system (OLVR) or submit a new voter registration application or a signed written request to the local Board of Elections, 18753 N. Frederick Road, Suite 210, Gaithersburg, MD. 20879. A written request must include complete name; date of birth; old and new change; date; and signature. The deadline to change your party affiliation for this election cycle was in April 2024. Changing political parties may be done anytime voter registration is open.
See link below for additional information, which includes voter registration and political parties hyperlinks.