Former President Donald Trump won a second term in the White House and his Republican Party took control of the Senate. But control of the House of Representatives is still in play, as is the size of the new majority in the Senate.

In the fight for the House, Democrats face an uphill climb to secure the four seats needed to flip the chamber, while Republicans only need to win a handful of more competitive races to maintain the majority. With more than a dozen House races still uncalled and many of them looking close, Democrats would need to keep all of their competitive seats and flip a few Republican-held seats to get the 218 seats needed for a majority.

While votes are still being counted, here’s a look at the key races that remain unannounced by the NBC News decision desk (read more at what are these races called). Even if some of the battleground states can be tossed relatively quickly, it could take days or even weeks to take control of the House.

Presidential Battlegrounds

With Trump’s victory in Michigan projected by NBC News on Wednesday afternoon, a victory in Nevada announced early Thursday morning, and a Trump victory declared in Arizona on Saturday evening, all presidential battleground states have now been announced.

Senate races still to be called

Arizona Senate: Democratic Rep. Ruben Gallego leads Republican Kari Lake in the vote count, but the race is still too early to call. Lake is trailing Trump in the state, while Gallego is outperforming Vice President Kamala Harris. Gallego, a Marine veteran, touted his military service in his race against Lake, a former local news anchor. Lake unsuccessfully ran for governor in 2022 and she made false claims that her 2022 run was affected by voter fraud.

Pennsylvania Senate: Even though Trump is expected to win Pennsylvania, the Senate race there is still too close to call. Democratic Sen. Bob Casey is seeking a third term against Republican Dave McCormick, a former hedge fund CEO who unsuccessfully ran for the GOP Senate nomination in 2022.

Online home control

Home control is still unclear, as important competitive races remain unannounced, including a number of key races in California alone. There are also other races that are not expected to be competitive but have not yet been projected because few votes have been counted.

Alaska At-Large District: Republicans are seeking to win this statewide seat, which Trump won easily. Republican Nick Begich is leading Democratic Rep. Mary Peltola, but he’s hovering around the 50% threshold needed to win the race. If he doesn’t reach that threshold, the race will go to a ranked-choice vote, but Republicans are confident they would still win the seat in that scenario.

1st District of Arizona: GOP Rep. David Schweikert is in a competitive race in suburban Phoenix against Democrat Amish Shah, a former state lawmaker.

Arizona’s 6th District: GOP Rep. Juan Ciscomani is trailing his Democratic opponent, former state Sen. Kirsten Engel, in this competitive suburban Tucson district.

9th District of California: Democratic Rep. Josh Harder narrowly leads his Republican opponent, Stockton Mayor Kevin Lincoln.

13th District of California: GOP Rep. John Duarte is in a tight race against Democrat Adam Gray, a former state lawmaker, in this Central Valley district.

21st District of California: Democratic Rep. Jim Costa is in a tight race with Republican Michael Maher, a former FBI agent, in this Fresno-area district.

22nd District of California: Leading his Democratic opponent, the former Rep. Rudy Salas State.

27th District of California: GOP Rep. Mike Garcia is in a tight race against Democrat George Whitesides, former NASA chief of staff and Virgin Galactic CEO, in this Southern California district.

41st District of California: Democrats have targeted this Riverside County-based district, and Republican Rep. Ken Calvert is in a competitive race with Democrat Will Rollins, a former prosecutor.

45th District of California: GOP Rep. Michelle Steel is leading Democratic army veteran Derek Tran in one of the most expensive races in the country.

47th District of California: Republicans are looking to flip this vacant Southern California seat, and Republican Scott Baugh, a former state lawmaker, is in a competitive race against former state Sen. Dave Min.

49th District of California: Also in Southern California, Democratic Rep. Mike Levin is in a tight race against car dealer Matt Gunderson, a self-described “pro-choice” Republican.

1st District of Iowa: Only a few hundred votes separate Republican Mariannette Miller-Meeks and Democrat Christina Bohannan, a former state representative. It’s familiar territory for Miller-Meeks, who won her 2020 race by just six votes.

2nd district of Maine: Democratic Rep. Jared Golden has been a top GOP target, and he sits just above the 50% threshold that would allow him to win over the Republican state representative. Austin Theriault, former NASCAR driver (the state organizes preferential elections). .

Ohio’s 9th District: Democratic Rep. Marcy Kaptur is in an extremely tight race with Republican state Rep. Derek Merrin.

Oregon’s 5th District: Democrat Janelle Bynum narrowly leads Republican Rep. Lori Chavez-DeRemer.

Washington’s 4th district: Republican Rep. Dan Newhouse narrowly leads Republican former NASCAR driver Jerrod Sessler. (The Washington primary advances the top two vote-getters to the general election, regardless of party.)

Sessler has Trump’s support over Newhouse, who is one of two remaining House Republicans who voted to impeach Trump after the January 6, 2021, riot at the Capitol.

This article was originally published on NBCNews.com