Politics and Geography

This article in the Atlantic provides an interesting and useful perspective on the correlation between red/blue and rural/urban.

The gap is so stark that some of America's bluest cities are located in its reddest states. Every one of Texas' major cities -- Austin, Dallas, Houston, and San Antonio -- voted Democratic in 2012, the second consecutive presidential election in which they've done so. Other red-state cities that tipped blue include Atlanta, Indianapolis, New Orleans, Birmingham, Tucson, Little Rock, and Charleston, S.C. -- ironically, the site of the first battle of the Civil War. In states like Nevada, the only blue districts are often also the only cities, like Reno and Las Vegas.