While tens of millions of early votes have already been cast, millions of Americans will still go to the polls on Election Day. Experts predict the 2024 election will be one of the closest in history, with several key states still fighting over who could choose the next president.

Vice President Kamala Harris and former President Donald Trump have been actively campaigning in several swing states in recent months. This year, seven swing states face off in intense competition: Arizona, Georgia, Michigan, Nevada, North Carolina, Pennsylvania and Wisconsin.

To win the White House, a candidate needs 270 electoral votes. Various combinations of the total of 93 electoral votes from these swing states will ultimately determine the winner.

Election Day is Tuesday, November 5, 2024. Election times vary depending on state law. Here's an update on three of the seven swing states in the final hours before the election.

In Pennsylvania, young voters are ready to make a difference

Pennsylvania is considered the key to the election with 19 electoral votes and many believe that the winner of Pennsylvania will be the next president.

In this battleground state, ABC News spoke with young voters who believe their vote could have a significant impact on this election. These voters have watched Harris and Trump often compete against each other in their state.

Both candidates held numerous stops and rallies on Monday.

Two first-time voters, 18-year-old Isaac Gourley and Caleb Root, will be at one of the thousands of polling places in Pennsylvania. They attend Redbank Valley High School in western Pennsylvania.

They have listened to both presidential candidates and will make their choice based on their priorities.

“What struck me was just their – international, so to speak – politics,” Gourley said. “You know, the way we talk to other people.”

About 50% of registered voters ages 18 to 29 voted in the 2020 election, an all-time high, according to a Tufts University study. In Pennsylvania, the rate was even higher than the national average: 54%.

“I pay a lot of attention to the economy,” Root said.

Pennsylvania's vote-counting rules suggest it could take days to determine the winner. Votes cast by mail cannot be counted until polls open at 7 a.m. on Election Day.

Helene will not stop voters in North Carolina

Despite initial concerns, voter turnout in the 25 North Carolina counties hardest hit by Hurricane Helene exceeded the statewide early voting average ahead of Election Day, with more than 760,000 ballots cast.

North Carolina and its 16 electoral votes are particularly important in the razor-thin contest between Harris and Trump. According to the latest NYT/Siena College poll, Harris has a slim lead over Trump in a race that remains too close to call.

In this historic turnout-driven election, both campaigns target women, the country's largest voter group.

An ABC News/Ipsos poll shows a clear gender divide among voters. Trump is up 5 points among male voters, while Harris is up 11 points among women.

During early voting, young women on the North Carolina State University campus marched to the polls with a pro-choice message and invited men to join them.

“I'm really scared that I feel like I don't know the rights I have as a woman,” said Lizzie Pascal, a student there.

Harris leads suburban voters nationwide by a total of 15 points; However, according to the latest ABC News/Ipsos poll, Trump has a four-point lead among white women. This demographic is widely believed to have contributed to his victory in 2016.

Sandy Joiner, president of the Western Wake County Republican Club, has worked to canvass Republican women vying for state and local seats.

“We knocked on about 12,000 doors in our region,” Joiner said. “And we knocked on all the doors, so we don't have any doors left. “What we're doing now is knocking on doors in areas that maybe haven't been reached yet.”

The same goals drive these women, whether they're encouraging voters to turn out in storm zones, suburbs or on college campuses. When all the votes are counted on and after election night, women are likely to be the key to who moves into the White House.

How Michigan is a must-win for both Trump and Harris

Experts say Michigan is a must-win for both sides, which is why both candidates campaigned extensively in the Great Lakes.

Once part of the Democrats' so-called “blue wall,” polls show Michigan — and its 15 electoral votes — are a mess.

While early voting shows a surge of women and young voters in college towns, one of the groups that was once solidly Democratic is no longer truly blue: union members.

ABC News spoke with Douglas King, an autoworker and UAW member for nearly 30 years. He says the economy, like so many other Americans, is his biggest issue.

“I was raised to believe that the Democrats were the party of working people,” King said. “And maybe they were once. Today I no longer feel that way.”

Many union leaders supported Harris.

In this hard-fought race, Harris's more than 500,000 union members are crucial; However, some of them seem to be moving away from voting for the Democratic Party. King, who voted for Barack Obama twice, has decided to support Trump for president for the third time.

“People are afraid to say they're voting for Trump because Trump supporters get pigeonholed as being these hateful, racist people who are homophobic, and that's just not true,” King said. “Trump has a lot of support in the factory.”

There are cracks in the old coalition that has consistently voted for the Democrats over the past 30 years. However, Trump broke the blue wall in 2016 by narrowly defeating Hillary Clinton in Michigan by around 10,000 votes.