Social Explorer users have access to a century of election data maps from Dave Leip's Atlas of U.S. Presidential Elections. Leading up to the November election, we are focusing on different election map features. (For an overview, get started with our introductory election maps post.)

Explore House of Representatives races by district from 2000 to 2014 with Social Explorer. Looking at the 2000 and 2014 maps side by side, you can see changes in the parties and margins of victory. 

These competitiveness maps give an overview of how close or far apart each race was (blue for Democrat, red for Republican and brighter colors for larger margins of victory). Mouseover to see the margin of victory in your district. Zoom in for more detail.

This next set of maps shows House elections from 2006 when Bush was president, and 2008 when Obama won his first presidential race. 

In the 2008 House election, the Democrats gained 32 seats and the Republicans lost 33 seats (leaving aside vacancies). Obama's popularity with voters helped bring many new Democrats into the House.

Just two years later, the pendulum swung the other way (and with twice as much power). The following pair of maps shows the 2008 and 2010 House elections. In 2010, the Republicans gained 64 seats and the Democrats lost 63 seats (leaving aside vacancies). Fewer voters turned out in the mid-term election, including many that voted for Obama and other Democrats in the 2008 election. Meanwhile the Tea Party movement increased in size and influence bringing motivated conservatives to the polls and into the halls of Congress. 

Use Social Explorer's election maps to learn more about shifts in the House.

Find out more about Social Explorer election maps through our other how-to blog posts between now and election day, and by watching our video with Social Explorer's Andrew Beveridge.