2008 Presidential Election Results by County - Margin of Victory Map

The following map shows all of the counties in the United States. Counties colored dark blue were won by Barack Obama by at least a 10% margin. Counties colored light blue were won by Barack Obama by less than 10%. Counties colored dark red were won by John McCain by at least a 10% margin. Counties colored pink were won by John McCain by less than 10%.

Analysis
Several things are notable about this map. One of the most apparent, and least surprising, is that most of the close counties (those colored light blue or pink) were in either rural areas or were suburbs of landslide counties (those colored dark blue or dark red). This is most obvious in the midwest, especially in Iowa, Wisconsin, Minnesota, and Michigan. In those states there were a lot of rural and suburban counties that either went narrowly to Obama or narrowly to McCain. It is not surprising that suburbs were battlegrounds in this election because they have been battlegrounds in past elections as well. The suburbs of major cities are very important for a candidate to win because of the large number of people that live there. The suburbs of the following cities were battleground areas: Denver, Albuquerque, Portland (Oregon), Minneapolis, Kansas City, St. Louis, Milwaukee, Detroit, Toledo, Pittsburgh, Philadelphia, Houston, Atlanta, Raleigh, Virginia Beach.