Two days after Election Day, three Senate races and 13 House races remain unresolved. A runoff later this month will determine the winner of the Senate race in Mississippi.

House Democrats have already passed the threshold for a majority by winning 225 seats so far, wresting control of a chamber they haven’t held since 2010. Based on current projections, they could obtain as many as 234 seats — good for a 33-seat majority — though it is more likely they’ll land somewhere around 228 seats for a still-significant 21-seat margin.

In the Senate, the GOP not only held the line, but managed to flip Indiana, North Dakota and Missouri, states that President Donald Trump won by double digits in 2016.

Here are the outstanding races that will determine the size of the Republicans’ majority in the Senate and the Democrats’ majority in the House:

Senate

Florida

After three full terms (18 years) in the upper chamber, Democratic Sen. Bill Nelson of Florida called for a recount Wednesday after Republican Gov. Rick Scott declared victory Tuesday night. As of 9 a.m. Thursday, Scott led Nelson by 30,264 out of more than 8.1 million votes with all precincts reporting. State officials still need to count or verify straggling absentee and provisional ballots.

Nelson held a slight edge in the RealClearPolitics polling average heading into the night — though his lead was well within the margin of error, making Florida one of the night’s bigger upsets.

Arizona

GOP Rep. Martha McSally held a narrow lead of 17,073  votes over Democratic Rep. Kyrsten Sinema early Thursday morning as the secretary of state there waits on just seven more precincts out of 1,489 to report their results. Absentee and provisional ballots will also add to the vote totals in Arizona over the next few days.

Mississippi

The race for Mississippi’s junior Senate seat has been called, but there will not be a declared winner until a Nov. 27 runoff election.

GOP Sen. Cindy Hyde-Smith and former Democratic Secretary of Agriculture Mike Espy advanced to the runoff after Hyde-Smith failed to reach the 50 percent threshold for an outright victory. Republican Chris McDaniel siphoned off 16.4 percent of the vote from Hyde-Smith.

House

Republican incumbents

Four incumbent California Republicans are locked in close battles that The Associated Press had not called by Thursday morning. California’s 10th, 25th, 45th and 48th Districts were all either too close to call or had not received complete reports from their precincts.

Reps. Steve Knight and Dana Rohrabacher of the 25th and 48th Districts, respectively, trailed their Democratic challengers on Thursday. Reps. Jeff Denham and Mimi Walters paced the Democrats in their uncalled races with some mail-in ballots still uncounted.

In Georgia, GOP Rep. Rob Woodall led Democrat Carolyn Bourdeaux by 890 votes with all precincts reporting in the race for suburban Atlanta’s 7th District.

In the adjacent 6th District, GOP Rep. Karen Handel conceded defeat to Democratic activist Lucy McBath. McBath led Handel by roughly 2,100 votes with all precincts reporting.

Utah Rep. Mia Love, who spoke at the 2016 Republican National Convention and is the GOP’s only black woman in the House, trailed by 2.7 percent to Salt Lake County Mayor Ben McAdams with 70 percent of precincts reporting early Thursday in the 4th District.

With just absentee and provisional ballots left to count, Democratic challenger Anthony Brindisi led Rep. Claudia Tenney by 1,422 votes in New York’s 22nd District. Tenney, a fierce defender of the president, ran one of the most pro-Trump campaigns of any vulnerable Republican this cycle.

Democratic challenger and former Obama administration official Andy Kim held a lead of 2,622 votes over Rep. Tom MacArthur with 99 percent of precincts reporting Thursday morning.

Republican incumbents in Maine’s 2nd District (Bruce Poliquin), New York’s 27th (Chris Collins) and Texas’ 23rd (Will Hurd) held narrow edges in their respective races at noon on the East Coast, but those contests remained uncalled.

Open seats

Two open seats remain uncalled, with a pickup opportunity for Democrats still on the table.

By 9 a.m., Republicans were still holding on to narrow leads in California’s 39th District and North Carolina’s 9th District for open seats previously held by the GOP.

Watch: Now That That’s Over (Mostly) Roll Call Looks Ahead to 2020

Correction Friday, 1:59 p.m. | An earlier version of this story incorrectly stated that Florida Sen. Bill Nelson initially conceded his Senate race.