Factbox: These states are deciding the U.S. presidential election

These states play a critical role in delivering the 270 Electoral College votes needed to win the White House.

Of the 13 states on this watch list, seven remain undecided, four have gone to Trump and two have gone to Biden. None of the decided states represent a change from the 2016 election.

Due to a surge in mail voting amid the coronavirus pandemic - as well as the states' varying rules for when ballots can be counted - the final results for all the states may take days.

Electoral votes: 11

Polls have closed.

Rating in presidential contest: Leaning Democratic

Other key races: Democratic challenger Mark Kelly appears to have won the U.S. Senate seat currently held by Republican Martha McSally.

Vote counting: Two news organizations have called Arizona for Biden and for the Democrat Kelly in the Senate race. All absentee ballots had to arrive by the close of polls on Election Day. Ballots could be scanned and tabulated starting 14 days before Tuesday.

Electoral votes: 16

Rating in presidential contest: Leaning Republican

Other key races: The race for one U.S. Senate seat will proceed to a two-way runoff between a Democrat and a Republican as no single candidate received at least 50 percent of the vote. The other race is considered competitive.

Vote counting: No organization had yet to call the presidential contest nor the competitive Senate race. Absentee ballots had to be received by clerks by the close of polls on Election Day. Ballots could be opened and scanned on receipt, but they could not be tallied until after the polls closed on Tuesday. Officials in Fulton County, home to Atlanta and a tenth of all Georgians, warned on Tuesday that its vote count would not be finalized until Wednesday after a burst pipe delayed absentee-by-mail ballot processing for at least two hours, according to local reports.

Electoral votes: 20

Rating in presidential contest: Leans Democratic

Other key races: Competitive U.S. House contests in the 1st and 10th Districts

Vote counting: No organization had yet to call the presidential contest in Pennsylvania, nor for the close House races. Absentee ballot counting began at 7 a.m. on Election Day. Last week, the U.S. Supreme Court let stand a ruling by Pennsylvania's top court that officials in the state could accept mail-in ballots three days after Tuesday's election, so long as they were postmarked by Election Day.

Electoral votes: 10

Rating in presidential contest: Leans Democratic

Other key races: No governor or U.S. Senate races on the ballot

Vote counting: No organization had yet to call the presidential contest in Wisconsin. The state's election officials cannot count mail-in ballots that arrive after Election Day, the U.S. Supreme Court ruled on Oct. 26. Ballots could not be counted until polls opened on Tuesday. The Board of Elections director in Milwaukee County, the state's most populous, said on Tuesday evening that the county's presidential vote count would not be completed until at least 6 a.m. EST on Wednesday due to the amount of absentee ballots received.

Electoral votes: 16

Rating in presidential contest: Leans Democratic

Other key races: Competitive U.S. Senate contest

Vote counting: No organization has yet to call a winner in the presidential contest nor for the Senate race in Michigan. Absentee ballots had to arrive at clerks' offices by the close of polls on Election Day. Some densely populated jurisdictions in the state, such as Detroit, began sorting absentee ballots on Monday, but the vast majority did not. Clerks could begin scanning and counting absentee ballots at 7 a.m. on Tuesday. Michigan Secretary of State Jocelyn Benson said on Tuesday evening that she expected a fuller picture of the state's results in 24 hours. She said absentee ballots could top 3.3 million, while estimating in-person voting at 2 million to 2.5 million.

Electoral votes: 15

Rating in presidential contest: Leaning Republican

Other key races: Competitive U.S. Senate contest has not been called. Democratic Governor Roy Cooper appears to have won re-election.

Vote counting: No organization has yet to call a winner in the presidential election nor for the Senate race. Edison and three news organzations have called the govenor's race for Cooper, the Democrat.

North Carolina absentee ballots could be scanned weeks in advance, but results could not be tallied before Election Day. In a defeat for Trump, the U.S. Supreme Court declined last week to block the state's plan to tally ballots that are postmarked by Tuesday and arrive by Nov. 12.

Electoral votes: 6

Rating in presidential contest: Leans Democratic

Other key races: No governor or U.S. Senate contests on the ballot

Vote counting: No organization has yet to determine a winner in the presidential election. Absentee ballots could be processed upon receipt starting 14 days before the election, but results are not released until election night. Mail-in ballots postmarked by Tuesday will be counted so long as they arrive within seven days after the election.

Electoral votes: 38

Winner: Trump

Other key races: U.S. Senator John Cornyn, a Republican, appears to have won re-election.

Vote counting: Edison Research and six news organizations have called Texas for Trump. Edison Research and four news organizations have called the Senate race for Cornyn.

Electoral votes: 6

Winner: Trump

Other key races: U.S. Senator Joni Ernst, a Republican, appears to have won re-election.

Vote counting: Edison Research and six news organzitions have called Iowa for Trump. Edison Research and five news organizations have called the Senate race for Ernst.

Electoral votes: 29

Winner: Trump

Other key races: Scott Franklin, a Republican, appears to have won the race for U.S. Representative of the 15th District. Carlos Gimenez, a Republican, appears to have won the race for U.S. Representative of the 26th District.

Vote counting: Edison Research and six news organizations have called Florida for Trump.

Electoral votes: 18

Winner: Trump

Other key races: U.S. Representative Steve Chabot, a Republican, appears to have won re-election in the 1st District.

Vote counting: Edison Research and six news organizations have called Ohio for Trump.

Electoral votes: 4

Winner: Biden

Other key races: Governor Chris Sununu, a Republican, appears to have won re-election.

Vote counting: Edison Research and six news organizations have called New Hampshire for Biden. Edison Research and three news organizations have called the governor's race for Sununu.

Electoral votes: 10

Winner: Biden

Other key races: Competitive contests for the U.S. Senate and U.S. House in the 1st and 7th Districts