Md. Code, Election Law § 8–201

(a) (1) There shall be a statewide primary election in every even–numbered year.

(2) A primary election shall be held:

(i) in the year in which the Governor is elected, on the fourth Tuesday in June; and

(ii) in the year in which the President of the United States is elected, on the fourth Tuesday in April.

(b) In Baltimore City, there shall be a primary election for municipal offices on the fourth Tuesday in April in the year in which the President of the United States is elected.