Researchers, scholars, and policymakers interested in the falling rate of violent crime in New York City (NYC) have attempted to pinpoint causes of the welcome trend. Discovering the causes of the city’s crime drop may lead to important lessons for the city itself and may influence policy and practice throughout the state, nation, and perhaps other countries. Researchers have suggested a host of mechanisms that may explain the dramatic decline in violence, but two factors—misdemeanor policing and the transformation of drug markets—continue to receive the most attention. This report focuses on these factors in relation to gun-related homicide rates. It describes and maps precinct-level relationships between misdemeanor policing, drug markets, and gun-related homicide rates from 1990 to 1999 in NYC. An increase in misdemeanor policing is related to a decrease in homicide in some, but not all, precincts. Similarly, a decrease in drug use is not consistently related to homicide decline. There is substantial heterogeneity in the social processes associated with the decline in violent crime and a few select precincts may be responsible for driving aggregate level trends.