The criminal offense of unlawful assembly generally means the assembly of multiple persons resulting in conduct that (1) is intended to commit a breach of the peace or other unlawful act; (2) creates an immediate danger of damage to property or injury to persons; (3) substantially obstructs law enforcement or other governmental functions or services; (4) is tumultuous or violent and likely to cause public alarm; or (5) deprives any person of a legal right or disturbs any person in the enjoyment of a legal right by using force or the threat of force.

Unlawful assembly laws vary from state to state and some states have related offenses such as rioting, riots and routs, participating in a riot, inciting a riot, failing to disperse, and disturbing the peace. The criminal offense of unlawful assembly may be included in the definition of one or more of these offenses or may be a separate criminal offense. These laws are generally located in a state’s statutes—often in the penal or criminal code.

In Montana, the criminal offense of unlawful assembly is addressed under the Montana Code Annotated (MCA). Specifically, the offense is typically found in the sections dealing with public order and safety. According to Montana law, an unlawful assembly may occur when three or more persons assemble with the intent to commit an unlawful act, or when an assembly conducts itself in a tumultuous and violent manner that causes or is likely to cause public alarm. The law also covers situations where the assembly leads to the obstruction of law enforcement or other governmental functions. Related offenses, such as rioting or failure to disperse, are also defined in the Montana statutes. These offenses include participating in a riot, inciting a riot, and failing to disperse when lawfully commanded to do so by a peace officer. The penalties for these offenses can vary, but they generally include fines, imprisonment, or both. It is important for individuals in Montana to understand that while peaceful assembly is protected by the First Amendment, assemblies that turn violent or disruptive may lead to criminal charges under state law.