Key Southern California House races could shape balance of power. See updated results

Control of the U.S. House of Representatives could come down to a few key competitive races that are up to Southern California voters to decide.

After the dust settled from the March California Primary, featuring races with larger fields of candidates vying for votes, the top two finishers in each race are set for the high-stakes November runoffs.

While Democrats hold every major statewide office and outnumber registered Republicans in California 2 to 1, there are pockets of strong support for Republican candidates in parts of Southern California. Adding to the uncertainty, several California Republicans are representing districts that President Biden won in 2020, making the region a wildcard player in the makeup of the U.S. House.

All 435 U.S. House seats are up for election in 2024. Republicans have 220 members to Democrats' 212. There are three vacancies.

Here are some key Southern California U.S. House races with results from the March primary election.

U.S. House District 27

Rep. Mike Garcia won this district north of Los Angeles in 2022 by 6 percentage points over Democrat Christy Smith and held on to advance from the March primary. George Whitesides, the former CEO of Virgin Galactic, finished second in the primary and will challenge the incumbent in the General Election in one of five California districts that voted for Joe Biden in 2020.

It's also a district that favored Republican Brian Dahle by a slight margin over Gov. Gavin Newsom in the 2020 gubernatorial election.

Garcia, who served in the U.S. navy and U.S. Navy Reserve, was first elected in a special election in 2020. The special election was called after Democrat Katie Hill, who defeated a Republican in 2018, resigned due to a sex scandal. He won re-election over Smith in 2022, 53.2 percent to 46.8 percent.

Whitesides served as NASA chief of staff in the Obama Administration.

The district in northern Los Angeles County includes Santa Clarita, Lancaster, Palmdale and other high desert communities.

U.S. House District 40

GOP Rep. Young Kim is serving a second term after winning the district two years ago by 14 percentage points. Kim, one of three Korean American women who were the first elected to Congress in 2020, served the California Assembly for two years.

Kim will face former fire captain and union president Joe Kerr in the November election. Kerr served for more than 30 years with the Orange County Fire Authority. He also was president of the Orange County Professional Firefighters Association labor union. Kerr was unsuccessful in his 2022 bid for a state Senate seat and the Orange County Board of Supervisors in 2018.

The district includes parts of Orange, San Bernardino and Riverside counties The communities of Aliso Viejo, Corona, Chino Hills, Lake Forest, Mission Viejo, Rancho Santa Margarita, Tustin and Villa Park in the 40th District.

President Biden won the district by a slim margin in 2020.

President Biden won the district by a slim margin in 2020. Registered Republicans outnumber Democrats in the district by a margin of 38 percent to 34 percent, as of September.

U.S. House District 41

This sprawling Congressional district in Riverside County is headed for a rematch. Long-time Republican Rep. Ken Calvert won the race over Democrat Will Rollins.

The two were separated by less than 5 percentage points in the 2022 election.

Calvert is the longest-serving Republican in the California congressional delegation, having held his seat in this district east of Los Angeles since 1993. Rollins, a former federal prosecutor, gets another chance to unseat the incumbent in November.

Of note: Palm Springs has been added to this district since the last election.

The district also includes Menifee, Lake Elsinore, Rancho Mirage, most of Corona and Palm Desert.

U.S. House District 45

Rep. Michelle Steel easily advanced from the primary in her race against four Democrats, including second-place primary finisher Derek Tran, a veteran and civil rights attorney. Tran had only 16 percent of the vote to Steel's commanding 55 in the crowded primary.

This district supported Joe Biden for president in 2020, but voted for Republican John Cox over Gavin Newsom in the 2018 gubernatorial election. Registered Democrats outnumber Republicans, but Steel defeated a Democrat in 2020 before winning re-election in 2022.

District 45, which re-elected Steel with 52.4% of the vote in 2022, includes parts of Orange and Los Angeles counties. The district includes Garden Grove, Westminster, Buena Park and Artesia. Parts of Brea, Lakewood, Fullerton and Yorba Linda are in the district that's shaped like a C and wraps around Anaheim.

U.S. House District 47

This once solidly Republican district that stretches from Huntington and Newport beaches on the Orange County coast and inland to Irvine is the only open House seat among California's most competitive races. The seat was vacated by Katie Porter, who was running for Senate, but did not advance from the March primary and is not seeking re-election.

Scott Baugh, who lost to Porter by less than 4 percentage points in 2022, and Democratic state Sen. Dave Min are heading to a runoff. Baugh won the primary with 32 percent of the vote. Min was second at just under 26 percent with the remaining votes divided among other candidates.

The district had been represented by Republicans from the time it was created until Porter defeated then-Rep. Mimi Walters in 2018.

U.S. House District 49

Democratic U.S. Rep. Mike Levin advanced to defend his seat in this Southern California district that includes portions of Orange and San Diego counties.

Voters chose Levin in 2018 to replace longtime Republican Darrell Issa, who has since returned to Congress in a neighboring district. Levin has since been reelected twice — by six points in 2020 and 5 points in 2022.

This time around, he'll face a challenge from Republican Matt Gunderson, a car dealership owner who failed in a bid for state Senate in 2022. Gunderson chairs the Mission Hospital Foundation Board and was on the Saddleback College Foundation Board.

Cities in the district include Oceanside, Carlsbad, Encinitas and the southern Orange County communities of San Clemente, Dana Point, San Juan Capistrano, Laguna Niguel and Ladera Ranch.