Maryland Public Safety Section 5-133
(a)   This section supersedes any restriction that a local jurisdiction in the State imposes on the possession by a private party of a regulated firearm, and the State preempts the right of any local jurisdiction to regulate the possession of a regulated firearm.
(b)   A person may not possess a regulated firearm if the person:
(1)   has been convicted of a disqualifying crime;
(2)   has been convicted of a violation classified as a common law crime and received a term of imprisonment of more than 2 years;
(3)   is a fugitive from justice;
(4)   is a habitual drunkard;
(5)   is addicted to a controlled dangerous substance or is a habitual user;
(6)   suffers from a mental disorder as defined in § 10-101(f)(2) of the Health - General Article and has a history of violent behavior against the person or another, unless the person has a physician's certificate that the person is capable of possessing a regulated firearm without undue danger to the person or to another;
(7)   has been confined for more than 30 consecutive days to a facility as defined in § 10-101 of the Health - General Article, unless the person has a physician's certificate that the person is capable of possessing a regulated firearm without undue danger to the person or to another;
(8)   is a respondent against whom a current non ex parte civil protective order has been entered under § 4-506 of the Family Law Article; or
(9)   if under the age of 30 years at the time of possession, has been adjudicated delinquent by a juvenile court for an act that would be a disqualifying crime if committed by an adult.
(c)   (1)   A person may not possess a regulated firearm if the person was previously convicted of:
(i)   a crime of violence; or
(ii)   a violation of § 5-602, § 5-603, § 5-604, § 5-605, § 5-606, § 5-607, § 5-608, § 5-609, § 5-612, § 5-613, or § 5-614 of the Criminal Law Article.
(2)   A person who violates this subsection is guilty of a felony and on conviction is subject to imprisonment for not less than 5 years, no part of which may be suspended.
(3)   A person sentenced under paragraph (1) of this subsection may not be eligible for parole.
(4)   Each violation of this subsection is a separate crime.
(d)   (1)   Except as provided in paragraph (2) of this subsection, a person who is under the age of 21 years may not possess a regulated firearm or ammunition solely designed for a regulated firearm.
(2)   Unless a person is otherwise prohibited from possessing a regulated firearm, this subsection does not apply to:
(i)   the temporary transfer or possession of a regulated firearm or ammunition solely designed for a regulated firearm if the person is:
1.   under the supervision of another who is at least 21 years old and who is not prohibited by State or federal law from possessing a firearm; and
2.   acting with the permission of the parent or legal guardian of the transferee or person in possession;
(ii)   the transfer by inheritance of title, and not of possession, of a regulated firearm;
(iii)   a member of the armed forces of the United States or the National Guard while performing official duties;
(iv)   the temporary transfer or possession of a regulated firearm or ammunition solely designed for a regulated firearm if the person is:
1.   participating in marksmanship training of a recognized organization; and
2.   under the supervision of a qualified instructor;
(v)   a person who is required to possess a regulated firearm for employment and who holds a permit under Subtitle 3 of this title; or
(vi)   the possession of a firearm or ammunition for self-defense or the defense of others against a trespasser into the residence of the person in possession or into a residence in which the person in possession is an invited guest.