Gun crime is highly localized

From the FBI’s Supplemental Homicide Tables (2018):

  • 15 counties (out of 3,143), or 0.5% of all counties…
  • … with about 0.8% of the nation’s population…
  • had 25% of gun homicides.
  • About 50% of counties in any given year had zero gun homicides.
Illinois Firearm Homicide Share by County 2018

click to enlarge

In any given state, the concentration of homicides into one county is typical. For example, in Illinois, most homicides occur in Cook County (Chicago). In Maryland, 65% of gun homicides are in Baltimore City. In Tennessee, it is Shelby County (Memphis) with 45%.

Lack of policing and homicide resolution

In our study linked above, we asked why these 15 counties had 25% of gun homicides. Of the 26 variables we tested, understaffing of police departments and their associated low rate of solving homicides (AKA clearance rate) were the most important factors.