Compiled by Adam Levy and Robert Yoon, CNN Political Research
Arizona 1: Jonathan Paton (R) vs. former Rep. Ann Kirkpatrick (D)
Open Republican-held seat
This redrawn district covers most of northern and eastern Arizona. The Democratic nominee was Ann Kirkpatrick, who was elected in 2008 and was swept out in the Republican wave two years later. The Republican nominee was Jonathan Paton, a former state senator. Kirkpatrick had a sizable fund-raising advantage over Paton, but national Republicans invested heavily to help close the gap in TV ads. This seat was a top priority for both parties. Kirkpatrick was the projected winner.
Arizona 2: Rep. Ron Barber (D) vs. Martha McSally (R)
Democrat Gabrielle Giffords would have run here had she sought a fourth term. Giffords is recovering after being shot in January 2011 in Arizona. Her district director, Ron Barber, who was also wounded, won a special election to fill her seat when she resigned last January. His opponent was Republican Martha McSally, a retired Air Force colonel and combat pilot. Barber had a financial advantage at the start of October, though McSally remained competitive on the airwaves. Still, Barber was expected to win. A winner has not been yet projected.
Arizona 9: Kyrsten Sinema (D) vs. Vernon Parker (R)
The battle for this new district pitted Democrat Kyrsten Sinema, a former state senator, against Republican Vernon Parker, the former mayor of Paradise Valley. Both parties invested heavily in the race, though a Democratic super PAC tipped the TV ad war balance of power slightly in the Democrat's favor. A winner has not been yet projected.
California 30: Rep. Brad Sherman (D) vs. Rep. Howard Berman (D)
One of the nastiest House races of 2012 was between two incumbent Democrats due to redistricting and the state's new primary system, in which the top two finishers advanced to the general election. Rep. Brad Sherman had at least one advantage over Rep. Howard Berman: He represented more of the redrawn Sherman Oaks-area district. Sherman won the primary with 42.4% of the vote compared with 32.4% for Berman. The remaining votes were split among five candidates. The race hit a nasty patch last month, when the two men shouted at each other at a public forum. Sherman is the projected winner.
California 31: Rep. Gary Miller (R) vs. Bob Dutton (R)
Seven-term incumbent Rep. Gary Miller faced a tough challenge from a fellow Republican in a race also determined by California's new primary system. Miller's opponent was Bob Dutton, a state senator and businessman. Miller represented none of this redrawn district, while Dutton represented much of it in the state legislature. Miller is the projected winner.
California 36: Rep. Mary Bono Mack (R) vs. Raul Ruiz (D)
Rep. Mary Bono Mack, seeking an eighth full term in the House, was a frequent target of Democrats hoping to pick off a Republican in a Democratic district. This year, she found herself fending off a strong challenge from Democrat Raul Ruiz, a Mexican-American, Harvard-educated physician. But Bono Mack has survived strong challenges before and has a moderate voting record. She also prevailed over Ruiz in her first one-on-one matchup, the June "top-two" primary in which they appeared together on the same ballot. A winner has not been yet projected.
California 44: Rep. Laura Richardson (D) vs. Rep. Janice Hahn (D)
Redistricting forced another pair of Democratic incumbents to face off this November. Rep. Janice Hahn won a July 2011 special election to replace retiring Democratic Rep. Jane Harman. Rep. Laura Richardson was elected in a 2007 special election to replace the late Juanita Millender-McDonald. Hahn appeared to have an advantage due, in part, to an ongoing ethics saga for Richardson that resulted in a reprimand and $10,000 fine by the House Ethics Committee for campaign finance violations involving her congressional staff. Hahn also enjoyed a huge fund-raising and cash-on-hand advantage at the start of October. Hahn trounced Richardson in the primary. Hahn is the projected winner.
Florida 9: Former Rep. Alan Grayson (D) vs. Todd Long (R)
In just one term in Congress, Democrat Alan Grayson mastered the art of making headlines with his blunt and abrasive rhetorical style. During the debate over health care, he said the Republican health care plan was, "Don't get sick, and if you do get sick, die quickly." He also said on CNN that Republicans were "foot-dragging, knuckle-dragging Neanderthals." In a 2010 TV ad, he called his Republican opponent, Daniel Webster, "Taliban Dan." Although he quickly became a hero among liberals, Grayson went on to lose his bid for a second term by a staggering 18 points.
But Grayson won Tuesday in a new district in the Orlando suburbs against Todd Long, an attorney, small-businessman and conservative radio show host.
Florida 18: Rep. Allen West (R) vs. Patrick Murphy (D)
Rep. Allen West was a top target for Democrats The freshman Republican's sharp rhetoric during his first term did not endear him to colleagues across the aisle. For instance, West last summer e-mailed Democratic National Committee Chairwoman Rep. Debbie Wasserman Schultz that she was "the most vile, unprofessional and despicable member of the U.S. House of Representatives." West's Democratic opponent was Patrick Murphy, a businessman and executive with a construction firm. A winner has not been yet projected.