After months of enduring a barrage of expert opinions, opinion polls and advertising presentations, voters are finally having their say.

Millions of Americans across the country are ready to head to the polls where they will decide Tuesday whether to send Vice President Kamala Harris or former President Donald Trump to the Oval Office.

A fierce campaign exposed deep ideological divisions between the two parties and a gaping gender gap between Harris and Trump, with women supporting Harris by a margin of 16 percentage points and men supporting Trump by 18 percentage points, according to the latest NBC News poll.

More than 77.3 million people have already cast absentee and early in-person ballots, according to an NBC News analysis.

But both candidates believe their fate lies with seven battleground states that will ultimately decide the contest. Wisconsin, Michigan, Pennsylvania, Arizona, Nevada, Georgia and North Carolina ultimately consumed the campaign's most valuable resources: time and money. Hundreds of millions of dollars' worth of commercials flooded the airwaves in the battlegrounds as Harris and Trump held large-scale, competing rallies.

On Tuesday, Trump and his wife Melania want to vote in person in his home state of Florida. He will then host members and top donors for dinner at Mar-a-Lago, where he will spend the evening. Once the results are known, Trump will head to the Palm Beach County Convention Center.

Meanwhile, Harris, who wrapped up Monday night with a final rally at the Philadelphia Museum of Art on the steps made famous by the “Rocky” films, is back in Washington. She has already voted early by mail in California. She is expected to return to her alma mater, Howard University in Washington, on Tuesday evening after voting ends.

On the eve of the election, Harris and Trump headed to these swing states and made their final pitches, each focusing heavily on Pennsylvania, the states' biggest electoral gain.

Harris, who could become the first female president, campaigned on restoring abortion rights and protecting democracy while promising to support a “care economy” that supports first-time homeowners, small businesses and the elderly.

Trump often used dark — and sometimes violent — rhetoric, promising to stimulate the economy and deport millions of immigrants.

Both campaigns exuded confidence on Monday.

“Momentum is on our side. Can you feel it? We have momentum, right? Because our campaign spoke to the ambitions, aspirations and dreams of the American people,” Harris said in Allentown, Pennsylvania. “We are optimistic and excited about what we will do together, and we know here that it is time for a new generation of leadership in America.”

Trump made similar announcements at a rally in North Carolina.

“Hopefully everything goes well; We are groundbreaking. We just have to close it, we have to close it,” he said. “I actually hate that expression, but it's up to us to lose it. Does that make sense to you? It's up to us to lose. If we get everyone out and vote, they can't do anything. And if we don't, and if we don't, they're going to have to grab every person who ever signed anything in this terribly dangerous party that is going to destroy our country, and it's already destroying our country.”

The final day of the election caps a wild and sometimes harrowing 15 weeks after President Joe Biden withdrew from the Democratic nomination and threw his support behind Harris. Meanwhile, Trump suffered two assassination attempts, including one in which he was hit by a bullet.

Democrats welcomed Harris' entry into the race, setting fundraising records and volunteering and registering to vote in droves. Trump secured the Republican nomination even though he now has a criminal record and faces further crimes.

Meteorologists have been predicting a deadlocked contest for weeks that was within the polls' margin of error. The Harris campaign is flush with cash and has launched a massive campaign game in battleground states aimed at getting its voters to the polls. Republicans are concerned about their own ground operations after Trump outsourced recruiting efforts to third parties, which multiple reports have documented turmoil.

Harris campaign chairwoman Jen O'Malley Dillon said in a briefing with reporters on Monday that the campaign saw multiple paths to reach the 270 needed electoral votes, including the blue wall states of Wisconsin, Pennsylvania and Michigan, as well as in Arizona, North Carolina and Georgia. Biden won all of these states in 2020 except North Carolina.

“I would say that in Georgia we like what we see. We see that we are on track to win a very close race here. And in fact, as we looked day after day as the deadline got closer, we found that in Georgia in particular, the number of early voters was getting younger and more diverse every day,” O'Malley Dillon said. “We saw that African-American voters were a larger share of the overall vote, and we're seeing a pretty high number of our overall voter turnout overall.”

Trump's campaign boasted of strong early voting turnout among Republicans in states including Nevada, North Carolina and Georgia, a shift from 2020 after the party made a concerted push to gain points at the top.

“President Donald J. Trump enters Election Day stronger than ever before, and if patriots across the country maintain the momentum and perform as expected on Election Day, we will inaugurate President Trump in January,” says Tim Saler, a data consultant for Trump and the Republican National Committee said in a statement.

Harris' team warned Monday that election results could take a few days in some states, signaling that a delay in vote counting was to be expected and was not a sign of voter fraud. Trump, who has still not conceded his loss to Biden in 2020, has begun laying the groundwork for challenging the election results if he loses again.

Polls will begin closing completely across states at 7 p.m. ET, including in the battleground state of Georgia.