The crime of assault varies from state to state (and under federal law), but is generally defined as intentionally putting another person in reasonable apprehension or fear of an imminent (immediate) harmful or offensive contact. The crime of assault may be committed even if there is no physical contact, as the criminal physical contact constitutes the separate crime of battery. In many states assaulting a police officer or peace officer who is performing official duties (such as making a lawful arrest) is a more serious offense—sometimes a felony.

In Wyoming, assault is defined under state law as an unlawful attempt to cause bodily injury to another person, or intentionally causing bodily injury to another by use of force. The state differentiates between simple assault and aggravated assault. Simple assault, which may involve causing fear of imminent bodily harm without physical contact, is typically classified as a misdemeanor. Aggravated assault, which involves the use of a weapon or the intent to cause serious bodily harm, is a more serious offense and can be charged as a felony. Assaulting a police officer or peace officer in Wyoming is indeed considered a more serious crime. Under Wyoming statutes, causing or attempting to cause bodily injury to a peace officer, who is engaged in the lawful performance of his or her duties, is classified as a felony. This reflects the state's stance on protecting law enforcement officials while they are performing their official duties.