![b2c6bd7f-USA](https://a57.foxnews.com/static.foxnews.com/foxnews.com/content/uploads/2018/09/1200/675/Bono_Mack.jpg?ve=1&tl=1)
FILE: April 21, 2012: Mary Bono Mack at the GLAAD Media Awards in Los Angeles, Calif. (REUTERS)
The number of undecided House races is now at six – following Republican Rep. Mary Bono Mack’s concession late Friday night in her re-election effort in California.
Bono Mack lost to Democratic challenger Raul Ruiz after the remaining roughly 4,600 votes were counted.
"Today, I called Dr. Ruiz and congratulated him on his impressive victory,” Mack, who was seeking an eighth full term in the state's Riverside County-area district, said in a statement.
Ruiz, a physician, thanked Bono Mack for her public service and vowed to represent district residents of all party affiliations when he goes to Washington.
California now has two outstanding races, with Democratic challengers leading in both.
In the Sacramento County region, Rep. Dan Lungren was trailing Democratic challenger Ami Bera by 1,779 votes as of Friday night.
Lungren, who has held the seat since 2005, is chairman of the House Administration Committee, which leads orientation for new members.
In coastal San Diego County, Democrat Scott Peters is leading incumbent Republican Rep. Brian Bilbray by 814 votes.
Bilbray joined Congress as part of the 1994 Republican wave election and severed until 2001.
He was elected to the state’s 50th district in 2006 in a special election and this cycle ran as an incumbent in the newly redrawn 52nd district.
Peters is a former San Diego City Council president.
California law gives 28 days for results to be certified, so the impasses could last through early December. After results are certified, any candidate or voter can ask for a recount, which could take weeks.
House Republicans held a 242-193 majority before Tuesday. If Democrats win the six outstanding races, they will have a net gain of eight seats.
Perhaps the most closely watched, undecided race is on Florida’s Gold Coast where Republican Rep. Allen West appears to have lost to Democratic challenger and political newcomer Patrick Murphy.
The state on Saturday said a final but unofficial vote count shows West has lost by 2,442 votes. However, the Tea Party candidate has yet to concede. West has concerns about possible voting irregularities in St. Lucie County.
Arizona has two outstanding races, and results must be certified by Dec. 3.
In the Tucson-area race, Rep. Ron Barber, the former aide and successor to retired Rep. Gabby Giffords, trails Republican challenger Martha McSally by a slim 81 votes.
Republicans are optimistic about victory, saying areas in the state’s 2nd District, where ballots still must be counted, lean in McSally’s favor.
In the state’s 9th congressional district, Republican Vernon Parker was trailing Democratic challenger Kyrsten Sinema on Friday by roughly 3,800 votes. The lead appears to be increasing each day as new ballot-counts are being reported in the Phoenix-area race.
In North Carolina, incumbent Democratic Rep. Mike McIntyre leads Republican challenger David Rouzer by 507 votes in the state’s 7th congressional district.
McIntyre is among the last of the so-called Blue Dog Democrats, those in the party who represent conservative district and have attempted to caucus with Republicans. He and other members of the Blue Dog coalition have for Republicans more recently become a target for defeat.
Fox News’ Kara Rowland contributed to this report.