Maryland Statutes
Part II - Returns and Declarations Generally
Section 10-807 - Individual Returns -- Joint or Separate Return

(a)    Except as provided in subsection (b) of this section, a married couple who files a joint federal income tax return shall file a joint Maryland income tax return.
    (b)    A married couple who files a joint federal income tax return may file separate State income tax returns if:
        (1)    one spouse is a resident and the other spouse is a nonresident;
        (2)    the spouses are domiciled, or maintain principal places of abode, in different counties on the last day of the taxable year;
        (3)    the spouses have different taxable periods; or
        (4)    the Comptroller determines circumstances warrant.