Md. Code, Tax - General § 10–103

(a) Each county shall have a county income tax on the Maryland taxable income of:

(1) each resident, other than a fiduciary, who on the last day of the taxable year:

(i) is domiciled in the county; or

(ii) maintains a principal residence or a place of abode in the county;

(2) each personal representative of an estate if the decedent was domiciled in the county on the date of the decedent’s death;

(3) each resident fiduciary of:

(i) a trust that is principally administered in the county; or

(ii) a trust that is otherwise principally connected to the county and is not principally administered in the State; and

(4) except as provided in § 10-806(c) of this title, a nonresident who derives income from salary, wages, or other compensation for personal services for employment in the county.

(b) Except for the county income tax, a county, municipal corporation, special taxing district, or other political subdivision may not impose a general local income, earnings, or payroll tax, a general occupational license tax, or a general license or permit tax based on income, earnings, or gross receipts.