The party that will control the US House of Representatives – one of two chambers that makes up the United States Congress – remains up in the air.

The lower chamber currently has a Republican majority, which Democrats were hoping to flip with several key races.

Every seat in the House is up for grabs this election cycle. It’s important to note the final tally may not be known for several more days.

Republicans won several races on Tuesday, giving them control of the upper chamber, the Senate.

Here are some of the races that could determine control of the US House of Representatives:

Sarah McBride made history becoming the first trans member of the US House of Representatives after winning in her Delaware district on Tuesday evening.

McBride, who already broke history as the first openly transgender person ever elected to a state Senate seat, faced off against Republican John Whalen, a former Delaware state police officer.

She defeated Whalen in Delaware’s at-large congressional district – which encompasses all of Delaware – by 15 points.

“Delaware has sent the message loud and clear that we must be a country that protects reproductive freedom, that guarantees paid leave and affordable child care for all our families, that ensures that housing and health care are available to everyone and that this is a democracy that is big enough for all of us,” she wrote on X after the win.

In Virginia’s 2nd district, which encompasses Virginia Beach, Democrat Missy Cotter Smassal challenged the incumbent Rep Jen Kiggans, a Republican.

Votes still are being counted in the race between the two Navy veterans, but Kiggans led by four points as of Wednesday morning. It marks one of the most competitive races in the state.

Also in Virginia, two candidates are looking to fill Democrat Abigail Spanberger’s seat after she decided not to run for re-election and instead run for governor.

Republican candidate Derrick Anderson and Democrat Eugene Vindman are fighting to represent Virginia’s 7th district, which encompasses Fredericksburg and Culpeper in the northern part of the state.

The district flipped from red to blue – by narrow margins – in 2018 when Spanberger first won.

As of Wednesday morning, the race had not been called.

Pennsylvania’s 10th congressional district, in the south-central part of the state, is seeing a match-up between six-term incumbent Scott Perry and Democratic challenger Janelle Stelson.

Perry, former chair of the ultra-conservative House Freedom Caucus, has yet to face a strong challenger. He helped lead the Trump campaign’s efforts to overturn the 2020 election results.

Stelson is a former TV news anchor and former Republican who registered as a Democrat last year.

As of Wednesday morning, Perry was leading by less than one point, BBC’s US news partner CBS reported. But the race has not been officially called.

In Pennsylvania’s 8th district, Republicans flipped one seat in the district encompassing President Joe Biden’s hometown of Scranton.

Business owner Robert Bresnahan defeated incumbent Democratic Rep Matt Cartwright by two points. Cartwright has served six terms.

Republicans flipped four seats during the 2022 midterm elections that helped pave the way to capture the House.

Democrats were looking to win them back but saw mixed outcomes on Wednesday morning.

In the 17th congressional district, seen as one of the most contested swing districts in the US, incumbent Republican Rep Mike Lawler saw off a challenge from former Democratic Congressman Mondaire Jones.

But in the 19th congressional district, Democrat Josh Riley claimed victory, taking the seat from Republican Rep Marc Molinaro.

The rematch race in upstate New York was seen as one of the most expensive House races in the country. Molinaro won by just 4,500 votes in 2022.