With all 435 seats in the U.S. House of Representatives up for election on Tuesday, Republicans were expected to expand their majority amid dissatisfaction with President Barack Obama, whose approval ratings have dipped to 38 percent.

Republicans, who currently control 233 out of 435 seats in the House, may pick up 10 or more in Tuesday’s balloting — not enough to override a presidential veto but good for bragging rights as the party accumulates what could be its biggest majority since the late 1940s.

CALIFORNIA, District 7

In a state where urban areas tend to skew Democratic, the eastern suburbs of Sacramento have long been a battleground between Democrats and Republicans, and the state’s dramatic redistricting process two years ago created a district that could go back and forth between the two parties for years.

Democrat Ami Bera, a physician who eked out a win against the Republican who held the seat in 2012, faces a fierce battle against Republican Doug Ose in what has become one of the most closely watched contests in the country.

As of Oct. 15, Bera had raised $3.7 million during a campaign cycle that began in 2013, spending most of it to end the period with $347,000 cash on hand. Ose raised $1.6 million during the same period, and also reported loans of $1.8 million, according to federal campaign finance records.

CALIFORNIA, District 52

In a race that has been targeted as a priority by both parties, San Diego Democrat Scott Peters is nose-to-nose with challenger Carl DeMaio, who is openly gay and calls himself a “new generation Republican.” Both candidates are former San Diego City Council members.

COLORADO, District 6

After redistricting shifted a traditionally conservative district in Colorado so that it includes part of more liberal suburban Denver, Republican incumbent Mike Coffman found himself the target of a well-funded campaign by the Democratic former speaker of the Colorado House of Representatives, Andrew Romanoff.

The race has been one of the most expensive in the country, with Coffman raising $4.4 million during the 2013-2014 campaign cycle, and Romanoff raising $4.7 million.

FLORIDA, District 2

Winner: Democrat Gwen Graham

In Republican-leaning north Florida, Democrats won a rare upset against Tea Party Republican Steve Southerland, who has served two terms in the state’s 2nd Congressional District. With nearly all votes counted, challenger Gwen Graham led Southerland by just over a percentage point, with 50.6 percent of votes to Southerland’s 49.4 percent. The candidates were separated by 2,934 votes out of 245,444 cast.

Graham sought to unseat Southerland by playing up the enduring appeal of her family name, campaigning alongside her famous father, longtime U.S. Sen. Bob Graham.

Graham has downplayed her Democratic label, painting herself as an independent voice for the “North Florida Way.” The race was widely viewed as a test of her party’s ability to reconnect with white southern voters who have largely abandoned its national ticket.

FLORIDA, District 26

Winner: Republican Carlos Curbelo

Republicans in south Florida won back a seat they lost in 2012 in an all-Cuban-American tussle between incumbent Democrat Joe Garcia and rival Republican Carlos Curbelo. Curbelo led with 52 percent of the vote compared to Garcia’s 48 percent.

Garcia, 51, who conceded the race, was the first Cuban-American Democrat elected to Congress in Florida, after a long line of Republicans.

Curbelo, despite being only 34 and in his first congressional bid, is an experienced political hand, having run the campaigns of some senior south Florida Republicans. His hard-line anti-Castro conservatism appears to have stood him well with older Cuban-American voters.

IOWA, District 3

The contest between Republican David Young and Democrat Staci Appel remained extremely tight Tuesday night, as Young led by fewer than 2,000 votes out of 182,525 counted by 10 p.m. local time with about two-thirds of precincts reporting.

Democrats hoped to pick up a seat in Iowa in the close contest between the two, who are vying to replace Republican Tom Latham, who is retiring from a district that includes Des Moines, the largest city in the state.

A recent poll showed Appel ahead, but when the margin of error was considered, the race was nearly a tie.

MASSACHUSETTS, District 6

Winner: Democrat Seth Moulton

In northeast Massachusetts, four-tour Iraq war veteran Seth Moulton, a Democrat who ran a successful primary campaign against U.S. Rep. John Tierney, beat Republican former lawmaker Richard Tisei.

The race upended some typical assumptions about U.S. politics, with the Democrat campaigning hard on veterans’ issues, while Tisei, a gay man who is married, positioned himself as socially liberal.

In his victory speech, Moulton cited his service in the marines and said he would work on improvements to the Veterans Administration medical system, as well as lower taxes for small businesses and equal pay for women.

NEW YORK, District 11

In one of the more colorful races of the season, Republican Michael Grimm’s effort to hold on to his seat in New York’s 11th Congressional District after he was indicted for fraud, perjury and conspiracy in a tax fraud case has taken off in recent days.

The once-tight contest against Democrat Domenic Recchia Jr., a former City Council member, to represent the Staten Island district has opened up, with a wide 19-point lead for Grimm, according to the latest polling by Siena College with NY1 News and Capital New York.

Grimm famously made headlines earlier this year after he was caught on camera threatening to throw a reporter off a balcony in the U.S. Capitol, saying: “I’ll break you in half. Like a boy.”

NORTH CAROLINA, District 2

Leading: Republican Renee Ellmers

“American Idol” runner-up Clay Aiken, a Democrat, headed for another second-place finish in his challenge to U.S. Rep. Renee Ellmers in North Carolina’s heavily Republican 2nd Congressional District.

Ellmers, who won the seat during the Republicans’ national electoral sweep in 2010, opened up a wide lead over Aiken, with 59 percent of the vote compared to 41 percent for Aiken with 150 out of 157 precincts reporting Tuesday night.

Aiken, who taught special education in North Carolina before his 2003 “American Idol” stint, argues the district is ready for a representative who will spend more time listening to constituents back home and be less consumed by partisan politics.

TEXAS, District 23

Leading: Republican Will Hurd

With just over half the votes counted, incumbent Texas Democrat Pete Gallego was trailing Republican challenger Will Hurd, a former CIA operative who says his background gives him expertise in national security and public service.

The two are fighting over a district that stretches for 500 miles from San Antonio to El Paso and is bigger than 29 states, according to Gallego’s congressional website.

With 56 percent of the vote counted, Hurd led with 51.4 percent of the vote, compared to Gallego’s 46.4 percent.

UTAH, District 4

The Mormon daughter of Haitian immigrants, former Saratoga Springs Mayor Mia Love aims to become the first black Republican woman to be elected to the House.

Love is opposed to abortion and supports gun rights, and she holds a concealed weapons permit. She faces Democratic attorney Doug Owens in a district created after the 2010 Census that encompasses parts of Democratic-leaning Salt Lake City, then runs south along the Wasatch Front into parts of rural Utah that are typically Republican strongholds.

The most recent poll by UtahPolicy.com showed the race a virtual tie, with Love 48 percent to Owens 43 percent and a margin of error of plus or minus 4.89 percentage points.