The COVID-19 pandemic initiated once-in-a-lifetime increases in isolation. State-level policies, enacted with the goal of reducing COVID-19 prevalence, created unprecedented mobility restrictions which caused statistically and economically significant decreases in crime rates. A differences-indifferences analysis of all 50 U.S. states and the District of Columbia reveals isolation reduced the number of violent crimes committed, including homicide, the number of motor vehicle thefts, and the number of burglaries in the United States. The reduction of crimes observed as isolation increases has broad implications for stay-at-home policy decision making and post-pandemic law enforcement resource allocation.