(CNN) — The presidential race between President Donald Trump and former Vice President Joe Biden remains on razor’s edge as election workers in key states continue to plow through ballots.

Here’s what’s happening in each state:

Arizona 

Arizona Secretary of State Katie Hobbs said Thursday morning that approximately 450,000 ballots are left for the state to count — with about 300,000 of those coming from populous Maricopa County, which includes Phoenix and its suburbs.

Hobbs, speaking on NBC’s “Today” show, did not have an estimate on how long it would take for the remaining ballots to be counted.

She described the remaining ballots as including “early ballots that voters dropped off on election day at polling places.” She said workers Thursday morning were verifying signatures before the ballots could be tabulated.

The state does not count ballots received after Election Day.

Georgia

Nearly 48,000 remain to be counted in Georgia, according to a statement by Secretary of State Brad Raffensperger. Trump was ahead by fewer than 15,000 votes around midday Thursday, according to the latest reports. Sixteen electoral votes hang in the balance.

Chatham County, which includes Savannah, had the most ballots still uncounted Thursday morning, more than 17,000 votes.

Gabriel Sterling, a Georgia election official, said the state also is trying to determine how many outstanding provisional ballots still need to be counted, but he hoped that would be resolved by day’s end.

“Fast is great, and we appreciate fast,” he told reporters Thursday morning. “We more appreciate accuracy.”

Nevada 

It’s hard to determine how many ballots are outstanding in Nevada because the state is one of a handful that mailed ballots to all active registered voters. Election officials will count mail-in ballots received through November 10, as long as they are postmarked by Election Day.

Biden’s lead increased to nearly 12,000 votes in Nevada midday Thursday after an updated results release by the state. Officials in Clark County, home to Las Vegas and more than 70% of the state’s voters, said they expect to have all of their ballots counted by the end of the weekend.

In Washoe County, the state’s second largest county, officials say about 9,000 mail-in ballots currently are being tallied.

North Carolina

Trump leads in North Carolina by more than 75,000 votes, with an estimated 95% reported. The state is not expected to report any additional results until next week.

To finish its count, North Carolina is waiting to see if 116,000 outstanding requested absentee ballots are returned by November 12. In North Carolina, an Election Day-postmarked ballot can be counted if it is received by 5 p.m. ET on November 12.

But the state still does not know how many of those 116,000 voters chose to instead vote in person or drop off their ballot on Election Day, so the number of potential outstanding votes could shrink.

“With very few exceptions, North Carolina’s numbers are not going to move until November 12 or 13,” North Carolina State Board of Elections Executive Director Karen Brinson Bell said Wednesday.

Pennsylvania

In Pennsylvania, where 20 electoral votes are at stake, about 370,000 ballots remain to be counted Pennsylvania, state officials said. And Secretary of State Kathy Boockvar said that election workers could finish tallying “the overwhelming majority” on Thursday and have a clear winner.

Mail-in ballots continue to arrive in Pennsylvania where state law allows election officials to receive and count mail-in ballots that arrive by Friday. Boockvar has asked counties to segregate any ballots arriving between 8 p.m. ET November 3 and before 5 p.m. November 6 in light of a possible legal challenge from the Trump campaign.

But speaking on CNN Thursday afternoon, Boockvar said the post-Election Day ballot numbers could have a marginal impact on the outcome. “It’s not a huge number,” she said. “So, I think, no matter what happens, I don’t think it’s going to be a tremendous impact on this race.”

Allegheny County officials told CNN earlier in the day that they had received around 500 post-election ballots and estimate another 10,000 to 15,000 provisional ballots are left to be processed. Allegheny County includes the city of Pittsburgh.

Allegheny officials will not count any more ballots until Friday because of a court order over some 29,000 disputed ballots, according to county officials. But the county will still be preparing for a resumption Friday of the counting. “They’re processing them. No one has the day off. They’re working,” Allegheny Executive Rich Fitzgerald told CNN.

There are approximately 36,000 ballots left to count, Fitzgerald said.

This story has been updated with additional information.

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