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 Maryland, the criminal offense of unlawful assembly is addressed under the state's criminal law statutes. Specifically, Maryland law prohibits rioting and unlawful assembly under Maryland Criminal Law Code, Title 6, Subtitle 3. The law defines a riot as a public disturbance involving an assemblage of three or more persons which by tumultuous and violent conduct or the threat thereof creates grave danger of damage or injury to property or persons or substantially obstructs law enforcement or other government functions. Unlawful assembly in Maryland is generally described as a gathering of people with the intent to engage in conduct that presents a clear and present danger of rioting. The penalties for participating in a riot or an unlawful assembly can include imprisonment, fines, or both. Additionally, Maryland law also addresses related offenses such as failure to disperse when ordered by law enforcement and inciting or urging others to riot. An attorney can provide specific guidance on how these laws may apply to particular circumstances and the potential defenses that may be available to individuals charged with such offenses.