The Udall cousins took two Republican seats in the West. Rep. Tom Udall grabbed the seat being vacated by retiring Sen. Pete Domenici in New Mexico. In Colorado, Rep. Mark Udall won the seat of retiring Republican Sen. Wayne Allard.
Republicans hung on to a key post, however, with Senate Minority Leader Mitch McConnell retaining his seat by defeating Democrat Bruce Lunsford in Kentucky. Unseating McConnell would have been a coup for Democrats and an indication of voters' broad distaste for Republicans.
Turnout was high across the country with all 435 House members up for re-election. In the Senate, 35 of 100 seats had been in play, including 23 Republican and 12 Democratic seats. Slide show: America votes.
Obama won the presidency after picking up key victories in Florida, Pennsylvania and Ohio, defeating Sen. John McCain by a wide margin. See full story.
In Connecticut's Fourth District, Republican Chris Shays fell to Democrat Jim Himes, ending the Republican's 22-year House career. He was the last Republican congressman from New England.
Democrat Alan Grayson, an Orlando businessman and lawyer, ousted incumbent Republican Rep. Ric Keller of Orlando. And former state Rep. Suzanne Kosmas, a Democrat, unseated Rep. Tom Feeney, who was under fire for his ties to disgraced lobbyist Jack Abramoff.
Rep. Don Young, R-Alaska, won his 19th term despite an ongoing ethics investigation.
Pennsylvania Democrat Paul Kanjorski, who chairs a House Financial Services subcommittee, retained his seat despite tough Republican opposition.
At least four House Democrats went down to defeat, reports said. First-term Rep. Tim Mahoney of Florida was defeated after admitting to extramarital affairs, and Louisiana Democratic Rep. Don Cazayoux lost a seat he had secured just six months ago in a special election.