In 2020, the Associated Press and other media outlets determined that Joe Biden won the presidency four days after the election. The swing states that took the longest back then could be slow again this year: Pennsylvania, Arizona and Nevada. If the race is close, other states could join the list.

In addition to legal restrictions on when officials can count mail-in ballots, long lines at polling places at the end of the day can also slow the count, as voters waiting in line at closing time are still allowed to vote.

And then there are ballots from overseas voters and military personnel, which sometimes arrive after Election Day, as well as provisional ballots cast by voters whose eligibility is in question. In very close elections, the outcome is not clear until the final ballots are counted.

Here’s a look at the seven battlefield states and when results can be expected.

Pennsylvania

In 2020, the Associated Press called on the state to support Biden on the Saturday after Election Day. Election officials expect the count to take several more days this year.

Unlike many states, officials are not allowed to begin processing absentee ballots until 7 a.m. on Election Day. The process is laborious. Workers must verify that voters have provided all necessary information, then remove ballots from envelopes, unfold them, ensure they have not been damaged and insert them into ballot tabulators.

Pennsylvania has obscure rules that can lead to ballot challenges. Mail-in ballots must be placed in a secrecy envelope which is then placed in a mailing envelope. Envelopes must be correctly dated. If there are errors, the ballots cannot be counted.

Arizona

Four years ago, Fox News and the Associated Press called Arizona for Biden on election night, a move that others called premature. Most networks waited days to determine whether Biden had won the state. This time again, the unofficial results could take just as long.

Arizona allows election officials to process early ballots as soon as they receive them, but many voters wait until Election Day to cast them.

There are fears that vote counting in Arizona will take even longer this year because voting is unusually long. In Maricopa County, the state’s most populous county, election and election questions span two pages instead of one, meaning voters and officials will have to introduce twice as many pieces of paper. paper in the vote counting machines this year. This increases the risk of paper jams that slow down vote counting.

Nevada

In 2020, the Associated Press called Nevada for Biden on the Saturday after Election Day.

In Nevada, voting is largely done by mail, and Secretary of State Cisco Aguilar, a Democrat, has advised counties to begin tabulating those ballots as soon as polls open on Election Day instead. only after they close, as they have done in the past.

On Election Day, once the last voter has cast their ballot, the Secretary of State will give the green light to counties to release totals for all in-person ballots as well as all mail-in ballots that arrived before that time. day. What will be left will be in-person Election Day ballots as well as mail-in ballots arriving that day or later. Voting district totals will begin to be released Tuesday evening, but are unlikely to be fully released before the end of the week.

Most states require ballots to be returned by Election Day, but Nevada counts absentee ballots without a postmark that arrive up to three days after Election Day and those with a postmark from the post office up to four days after polling day. This creates uncertainty about when the results will be known, especially in the case of close elections. The second biggest day for receiving mail-in ballots in Nevada is usually the day after the election.

Georgia

Networks called Georgia for Biden on the Friday after the 2020 election. Election officials expect the count to go faster this year.

Election officials can process mail-in ballots as they arrive and begin counting them at 7 a.m. on Election Day.

An hour after polls close on Election Day — which is scheduled for 7 p.m. Eastern Time — state election officials plan to release tallies of all absentee and early ballots. treated. Early voting has been very popular this year, and more than half of registered voters have already cast their ballots. Officials estimate that most county Election Day tallies will be released by midnight Tuesday. They will also publish the total number of ballots cast that day, which will let the public know how many ballots remain to be counted.

A few laggards will take longer, including Fulton County, the state’s largest jurisdiction, which is operating a new counting facility this year.

Michigan

Michigan was called for Biden the day after Election Day. This year, Secretary of State Jocelyn Benson, a Democrat, said she hopes to have unofficial results for the state no later than the end of the day Wednesday.

This year, large and mid-sized communities began processing their absentee ballots last week; communities with fewer than 5,000 residents can process them Monday. All jurisdictions will count votes on Election Day.

In 2022, Michigan approved a measure allowing in-person early voting. Those who vote this way insert their ballots into tabulators, as they would on Election Day. That means less work for clerks on Election Day and should help speed up the count.

Wisconsin

In 2020, counting in Wisconsin ended early in the morning the day after Election Day, and the Associated Press called the state for Biden that afternoon.

Election officials cannot count early absentee and in-person ballots until after Election Day, which can cause delays in counting.

Milwaukee, a Democratic stronghold and the state’s largest city, is expected to be one of the last cities in the state to release its complete results as it needs time to count its early and mail-in ballots in its central central counting. Milwaukee’s elections director expects to have complete unofficial results shortly after midnight. A few other jurisdictions in the state could then report their results.

North Carolina

In the past, the state has released most results relatively quickly and could provide early clues about how Trump and Harris will fare nationally.

The counting process moves faster in North Carolina because election officials can remove mail-in ballots from their envelopes and feed them into tabulators weeks before Election Day. They tally these results on Election Day, but cannot announce the results until after the polls close at 7:30 p.m. Eastern Time.

Election officials will report totals for absentee ballots first, then totals for those who voted early in person or on Election Day.

Due to the damage caused by Hurricane Helene, some constituencies will have to communicate their results to electoral offices instead of delivering USB keys. This could slow down the reporting of results in some counties.