The legality of gun ownership in the United States

The shooting in San Bernardino on Dec. 2 was one in a heartbreakingly long line of mass shootings the U.S. has seen in recent years. The trend has spurred debates about gun control laws, due to the troubling fact that many mass shooters obtained weapons legally.

As the debate continues, and the nation grieves, it's worth reviewing some statistics to get a better sense of the situation in the United States and how it compares to the rest of the world. The above map, courtesy of Metrocosm, uses data from the Bureau of Alcohol, Tobacco and Firearms to show the numbers of federally registered weapons in each US state, broken down by weapon categories.

Go to the map and click on each state individually to check out its firearm statistics.

[Georgia Perry is a freelance writer based in Oakland, California. She's contributed to several print and online magazines including, The Atlantic, CityLab, Portland Monthly Magazine and the Portland Mercury. She was formerly a staff writer at the Santa Cruz Weekly in California. Follow her on Twitter @georguhperry.]