The SPLC maintains a detailed database on hate groups, culled from websites and publications, citizen and law enforcement reports, field sources and news reports. It defines hate groups as organizations and associations that "have beliefs or practices that attack or malign an entire class of people, typically for their immutable characteristics," and which participate in "criminal acts, marches, rallies, speeches, meetings, leafleting or publishing." As of 2010, the SPLC documents 1,002 such hate groups across the United States.

The map below, by Zara Matheson of the Martin Prosperity Institute, graphically presents the geography of hatred in America today. Based on the number of hate groups per one million people across the U.S. states, it reveals a distinctive pattern.

Hate groups are most highly concentrated in the old South and the northern Plains states. Two states have by far the largest concentration of hate groups -- Montana with 13.8 groups per million people, and Mississippi with 13.7 per million. Arkansas (10.3), Wyoming (9.7), and Idaho (8.9) come in a distant third, fourth, and fifth.

Hate groups are much less concentrated in the Northeast, Great Lakes, and the West Coast. Minnesota has the smallest concentration of hate groups, with 1.3 groups per million people, nearly ten times less than the leading state, followed by Wisconsin (1.4), New Mexico (1.5), Massachusetts (1.6), and New York (1.6). Connecticut (1.7), California (1.9), Rhode Island (1.9) all have less than two hate groups per million people.

But beyond their locations, what other factors are associated with hate groups? With the help of my colleague Charlotta Mellander, I looked at the social, political, cultural, economic and demographic factors that might be associated with the geography of hate groups. We considered a number of key factors that shape America's geographic divide: Red state/Blue state politics; income and poverty; religion, and economic class. It is important to note that correlation does not imply causation --we are simply looking at associations between variables. It's also worth pointing out that Montana and Mississippi are fairly extreme outliers which may skew the results somewhat. Nonetheless, the patterns we discerned were robust and distinctive enough to warrant reporting.

First of all, the geography of hate reflects the Red state/Blue state sorting of American politics.

Hate groups were positively associated with McCain votes (with a correlation of .52).

Conversely, hate groups were negatively associated with Obama votes (with a correlation of -.54).

Hate groups also cleave along religious lines. Ironically, but perhaps not surprisingly, higher concentrations of hate groups are positively associated with states where individuals report that religion plays an important role in their everyday lives (a correlation of .35).