Tracking the House’s Most Competitive Races

Representative Mary Peltola, the first Alaska Native in Congress and the first Democrat in half a century to represent the state in the House, is one of the most vulnerable Democrats in the country. Alaska has a ranked choice system in the general election, where her chief competitor is Nick Begich III, the Republican son of a prominent liberal political family in the state, whom she defeated in 2022.

Seven-term Representative David Schweikert, a Republican, has emphasized his fiscal conservatism as he seeks re-election in the wealthy Phoenix suburbs of Scottsdale and Pleasant Valley. He faces Democrat Amish Shah, a state representative and emergency room doctor who hopes to ride a wave of voter turnout boosted by an abortion rights measure on the ballot.

Representative Juan Ciscomani, a first-term Republican, is again facing Kirsten Engel, the Democrat he defeated in 2022 by fewer than 6,000 votes. Mr. Ciscomani has centered his campaign around border security and economic issues, while Ms. Engel has emphasized protecting reproductive rights after the overturning of Roe v. Wade.

A freshman who won his seat in one of the closest elections in the country in 2022, Representative John Duarte is considered one of the most vulnerable House Republicans. Duarte, who has labored to separate himself from the national Republican brand, is facing a rematch with Adam Gray, a Democratic former state assemblyman who lost to Duarte last cycle by just a few hundred votes.

With his roots as a dairy farmer and reputation for bucking his party, Republican Representative David Valadao has proved difficult to dislodge from his Central Valley seat. He was one of the 10 House Republicans who voted to impeach President Donald J. Trump. He faces a rematch challenge from Rudy Salas, a Democratic former state assemblyman.

Representative Mike Garcia, a Republican and former military pilot, has established a reputation in his Antelope Valley district as a relatively moderate lawmaker, helping him to survive successive Democratic efforts to unseat him. He faces a challenge this year from George Whitesides, a Democrat, the former NASA administrator and Virgin Galactic CEO.

Representative Ken Calvert, a Republican who has served more than three decades in the House, is in a rematch with Democrat Will Rollins, who came close to beating him in 2022 in the Palm Springs-based district. Rollins is casting himself as a fresh face who is willing to work across the aisle.

Representative Michelle Steele, a two-term Republican from Orange County, Calif., and the first Korean-American woman ever elected to Congress is battling for re-election in a district President Biden won in 2020. She has floundered on the issues of reproductive rights and abortion and is facing off against Derek Tran, a lawyer, Army veteran and the son of Vietnamese refugees.

Freshman Democrat Yadira Caraveo, a former doctor and political moderate who keeps a low profile, is fending off a challenge from Republican Gabe Evans, a state representative whose resume includes stints as an Army captain and police officer, in a newly created purple congressional district north of Denver.

Second-term Representative Mariannette Miller-Meeks, a Republican, is facing a rematch challenge from Democrat Christina Bohannan, a former law professor and state representative who has made protecting abortion rights the focal point of her campaign. Miller-Meeks has toiled to explain away her backing for a 2021 bill, the Life at Conception Act, that would have effectively criminalized abortions.

Freshman Republican Representative Zach Nunn, a former state legislator who serves in the Air Force Reserve, faces Democrat Lanon Baccam, an Army veteran and former federal Agriculture Department official. Baccam has attacked Nunn over his opposition to abortion rights, while Nunn has tried to tie the Democrat to Biden administration economic policies he contends have made Iowans' lives worse.

Third-term Representative Jared Golden, a Democrat, has managed to defy political gravity in a district that voted for Donald Trump in both 2016 and 2020 by frequently breaking with his party and courting Republican voters. This year, he faces his toughest challenge yet from Republican Austin Theriault, a state representative and former NASCAR driver endorsed by Mr. Trump.

Curtis Hertel, a Democratic former state senator, is focusing heavily on protecting abortion rights in his run to succeed Representative Elissa Slotkin, who vacated this competitive Lansing-based seat to run for Senate. Tom Barrett, the Republican, lost to Slotkin in 2022 and is betting he can prevail this time without an abortion referendum on the ballot or an incumbent in the seat.

With the retirement of Representative Dan Kildee, Democrats face a tough battle to hold this swing district in central Michigan. Democrat Kristen McDonald Rivet has stressed that she would protect abortion rights, while Republican Paul Junge has emphasized a crackdown on the border. Mr. Junge has previously made two unsuccessful runs for Congress.

Representative Don Bacon, a Republican, is facing a rematch challenge from Democrat Tony Vargas, a state senator, whom he beat by just 6,000 votes in 2022, to represent Omaha and the surrounding suburbs -- a swing district in an otherwise solidly red state. Bacon, a retired Air Force general, is considered a moderate, but Vargas has attacked him for his conservative stances, such as opposing abortion rights.

First-term Representative Gabe Vasquez, a Democrat, is in a rematch against former Representative Yvette Herrell, a Republican and former member of the ultraconservative Freedom Caucus whom he defeated in 2022 by fewer than 1,300 votes. Vasquez has focused his campaign in the swing district on the U.S.-Mexico border on protecting abortion access and reproductive rights, while Herrell has centered hers around border security and immigration.

Representative Anthony D’Esposito helped Republicans flip the House in 2022. Now, he is one of its most vulnerable members, defending a left-leaning Long Island seat amid questions about reporting that he put his lover on the payroll. He faces Democrat Laura Gillen.

Republicans believe Representative Mike Lawler is one of their most skillful incumbents. But he faces a stiff challenge from former Representative Mondaire Jones in the Hudson Valley. They spent much of the race competing over who is more moderate.

In a closely watched rematch of 2022, the Republican incumbent, Marc Molinaro, takes on Josh Riley. Molinaro, known as one of the most bipartisan members of Congress, has veered to the right this cycle, leaning on fears about immigration.

Freshman Representative Don Davis, a Democrat, Air Force veteran and former college professor who frequently breaks with his party, faces a challenge from Republican Laurie Buckhout, a Trump-endorsed retired Army colonel and defense consultant from Virginia, in the sole competitive House race in the state.

House Republicans see the seat currently held by Representative Emilia Sykes, a first-term Democrat, as one of their best pickup opportunities in the country. Kevin Coughlin, a businessman and former state lawmaker who represented a similarly moderate district in the state legislature more than decade ago, has re-entered politics with the hope of unseating Sykes.

First-term Representative Lori Chavez DeRemer, a mainstream Republican who has endorsed former President Donald J. Trump, is running against Democrat Janelle Bynum, a state representative. inn a district that stretches from Portland’s southern suburbs to the rapidly growing town of Bend. Both candidates are pitching themselves as independent thinkers who can work across party lines.

Democratic Representative Susan Wild, who has held this competitive seat since 2018, has vastly out-raised her Republican challenger as she seeks a fourth term. But the district is favorable ground for Republicans, and Republican Ryan Mackenzie, a member of the state legislature, is running on an "America First" message associated with former President Donald J. Trump.

Representative Matt Cartwright, a Democrat, has represented this Scranton-area district for more than a decade, but it remains one of the true swing districts in the country. An Erie native, Cartwright is the only member of the Congressional Progressive Caucus to carry a district won by former President Donald J. Trump. He faces Rob Bresnahan Jr., whom Republicans believe has a solid chance to capture the seat.

Democrat Yevgeny Vindman, a retired Army lieutenant colonel and lawyer who teamed with his twin brother in a whistleblower account that became the basis of the first impeachment case against President Donald J. Trump, is making his first foray into politics seeking to succeed retiring Representative Abigail Spanberger. He faces Derrick Anderson, a Republican and former Green Beret.

Representative Marie Gluesenkamp Perez, a first-term Democrat representing a rural, working class district that former President Donald J. Trump won twice, is considered the most vulnerable Democrat in the House. She has frequently broken with her party on major votes and is is in a rematch against Joe Kent, a far-right election denier whom she beat in 2022 by less than 1 percentage point.