The laws governing the legal use, storage, carrying and transporting of firearms are constantly changing. Below are the applicable laws in the State of Montana as of 10/12/2013. The below information is designed to be a guide and not the final word. If you have specific questions, please refer to Montana legislation at leg.mt.gov.   If you have any specific questions concerning Castle Doctrine/Self-Defense laws in any state, American Firearms Training recommends contacting an attorney.

The Castle Doctrine (also known as Castle Law, Defense of Habitat Law) are state legal defense laws that gives citizens in their homes/abode, and in some states, cars or workplaces the right to protect themselves, other people, and their property by force. In some instances this includes deadly force without the consequences of legal or possibly civil responsibility and criminal persecution. A Castle Doctrine also states that a person has no “duty of retreat” (avoid the conflict at all cost) when one’s home/abode is under attack.

Some states will include in their Castle Law a “Stand Your Ground” clause. This clause removes the “duty of retreat” even outside of one’s home (car, work, where one is allowed to be and possess a firearm).

The State of Montana does have a Castle Law and a "Stand Your Ground" clause variation.  These and other self-defense laws can be viewed below.

45-3-101. Definitions.

(1) "Force likely to cause death or serious bodily harm" within the meaning of this chapter includes but is not limited to:
(a) the firing of a firearm in the direction of a person, even though no purpose exists to kill or inflict serious bodily harm; and
     (b) the firing of a firearm at a vehicle in which a person is riding.

(2) "Forcible felony" means any felony which involves the use or threat of physical force or violence against any individual.

45-3-102. Use of force in defense of person. A person is justified in the use of force or threat to use force against another when and to the extent that the person reasonably believes that the conduct is necessary for self-defense or the defense of another against the other person's imminent use of unlawful force. However, the person is justified in the use of force likely to cause death or serious bodily harm only if the person reasonably believes that the force is necessary to prevent imminent death or serious bodily harm to the person or another or to prevent the commission of a forcible felony.

45-3-103. Use of force in defense of occupied structure.

(1) A person is justified in the use of force or threat to use force against another when and to the extent that the person reasonably believes that the use of force is necessary to prevent or terminate the other person's unlawful entry into or attack upon an occupied structure.

(2) A person justified in the use of force pursuant to subsection (1) is justified in the use of force likely to cause death or serious bodily harm only if:
     (a) the entry is made or attempted and the person reasonably believes that the force is necessary to prevent an assault upon the person or another then in the occupied structure; or
     (b) the person reasonably believes that the force is necessary to prevent the commission of a forcible felony in the occupied structure.

45-3-104. Use of force in defense of other property.

A person is justified in the use of force or threat to use force against another when and to the extent that the person reasonably believes that the conduct is necessary to prevent or terminate the other person's trespass on or other tortious or criminal interference with either real property, other than an occupied structure, or personal property lawfully in the person's possession or in the possession of another who is a member of the person's immediate family or household or of a person whose property the person has a legal duty to protect. However, the person is justified in the use of force likely to cause death or serious bodily harm only if the person reasonably believes that the force is necessary to prevent the commission of a forcible felony.

45-3-105. Use of force by aggressor.

The justification described in 45-3-102 through 45-3-104 is not available to a person who:
(1) is attempting to commit, committing, or escaping after the commission of a forcible felony; or

(2) purposely or knowingly provokes the use of force against the person, unless:
     (a) the force is so great that the person reasonably believes that the person is in imminent danger of death or serious bodily harm and that the person has exhausted every reasonable means to escape the danger other than the use of force that is likely to cause death or serious bodily harm to the assailant; or
     (b) in good faith, the person withdraws from physical contact with the assailant and indicates clearly to the assailant that the person desires to withdraw and terminate the use of force, but the assailant continues or resumes the use of force.

45-3-106. Use of force to prevent escape.

(1) A peace officer or other person who has an arrested person in custody is justified in the use of force to prevent the escape of the arrested person from custody that the officer or other person would be justified in using if the officer or other person were arresting the person.
    

(2) A guard or other peace officer is justified in the use of force, including force likely to cause death or serious bodily harm, that the guard or officer reasonably believes to be necessary to prevent the escape from a correctional institution of a person whom the guard or officer reasonably believes to be lawfully detained in the institution under sentence for an offense or awaiting trial or commitment for an offense.

45-3-107. Use of force by parent, guardian, or teacher. 

A parent or an authorized agent of a parent or a guardian, master, or teacher is justified in the use of force that is reasonable and necessary to restrain or correct the person's child, ward, apprentice, or pupil.