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 Nevada, the criminal offense of unlawful assembly is addressed under Nevada Revised Statutes (NRS) 203.020, which defines 'unlawful assembly' as any assembly of two or more persons for the purpose of committing an unlawful act, or for the purpose of committing a lawful act in a manner likely to produce a breach of the peace. The statute makes it a misdemeanor to participate in an unlawful assembly. Additionally, Nevada law under NRS 203.030 and 203.040 also covers the offenses of 'rout' and 'riot,' respectively, which involve similar elements of group conduct leading to violence or disturbances of the peace. The crime of 'inciting to riot' is defined in NRS 203.070, making it unlawful for a person to incite or procure others to engage in a riot. Penalties for these offenses can include fines and imprisonment. It is important for individuals in Nevada to understand that while peaceful assembly is protected by the First Amendment, activities that cross the line into unlawful assembly or rioting can result in criminal charges.