Md. Code Ann., Tax-Prop. § 1-202 — § 1-202

(a) A person doing business in the State is deemed a resident of the State and of the county and any municipal corporation where the business is conducted if personal property is used in or in connection with the business.
(b) A personal representative of the estate of a decedent is deemed a resident of the county where appointed.
(c) A guardian is deemed a resident of the county where appointed.