Mark Follman, Gavin Aronsen, and Deanna Pan: “On December 14, a mass shooter killed 27 people at an elementary school in Newtown, Connecticut. Among the fatalities were 20 children, six adults, and the shooter, who also killed his mother at her home. More details here. This guide and map have been updated with data from the Newtown massacre. It’s perhaps too easy to forget how many times this has happened. The horrific mass murder at a movie theater in Colorado on July 20, another at a Sikh temple in Wisconsin on August 5, another at a manufacturer in Minneapolis on September 27—and now the unthinkable nightmare at a Connecticut elementary school on December 14—are the latest in an epidemic of such gun violence over the last three decades. Since 1982, there have been at least 62 mass murders* carried out with firearms across the country, with the killings unfolding in 30 states from Massachusetts to Hawaii. We’ve mapped them below, including details on the shooters’ identities, the types of weapons they used, and the number of victims they injured and killed.” See also

• GunPolicy.org provides evidence-based, public health-oriented information on armed violence around the globe
• CDC’s Firearm Death and Death Rates, 1999-2010
• Interactive Map: The U.S. Shooting Epidemic, by Brian Abelson & Michael Keller. Roll over or tap the interactive map [in this site] to see how your state compares, or explore the data in the spreadsheet.”