You'd be surprised. The electoral map below shows who, where, and in what concentrations, voters cast their ballots for Barack Obama and Mitt Romney (click on this link to see the high resolution version)
What's instructive is to see how blue-purple the electoral map really is. Even in "solid" Red States such as Texas, Idaho, Alabama (even Utah) Obama received high concentrations of votes in many areas of the states he didn't ultimately win, especially in suburban and urban areas.
What this tells us is the pendulum has swung - and hard - from the 2010 mid-term elections.
Remember that the next time Right Wing pundits try to convince you Democrats don't have a mandate coming out of the November 6th election.