A person generally commits the criminal offense of rape by using force, threats of force, coercion, or fraud to have non-consensual sexual intercourse with another person. In some states this criminal offense is called sexual assault. Rape is a felony offense with significant jail or prison time as potential punishment.

Laws vary from state to state and some state laws also include in the definition of rape sexual intercourse with a person who is intoxicated by drugs or alcohol, unconscious, or mentally disabled and unable to consent to the sexual intercourse. And some states have a broad definition of the lack of consent to sexual contact constituting rape and include sexual contact with public servants (police officers, etc.), members of the clergy, mental health service providers, and employees of assisted living centers or nursing homes as lacking consent under some circumstances.

In some states it is rape or sexual assault for a health care services provider performing an assisted reproduction procedure to use human reproductive material from a donor other than the patient’s intended donor.

Rape or sexual assault laws are generally located in a state’s statutes—often in the penal or criminal code.

In Montana (MT), rape, legally referred to as 'sexual intercourse without consent,' is a serious felony offense under Montana Code Annotated § 45-5-503. The law defines the crime as knowingly having sexual intercourse with another person without that person's consent. Consent is defined as words or overt actions indicating a freely given agreement to have sexual intercourse. Force, threats of force, coercion, or fraud can vitiate consent, making the act non-consensual and thus constituting rape. Additionally, Montana law considers sexual intercourse without consent with an individual who is mentally incapacitated, physically helpless, or subjected to coercive or fraudulent behavior as rape. The state's statutes also recognize that certain individuals, such as those who are intoxicated, unconscious, or mentally disabled, may be incapable of giving consent. Penalties for rape in Montana are severe and can include lengthy prison sentences. It is important for individuals to understand that consent must be freely given and that any sexual act without consent may be prosecuted under Montana's criminal laws. An attorney can provide more detailed information about the specific circumstances that may constitute rape or sexual assault in Montana.