This state could determine whether Trump or Harris wins the presidential election

Former President Donald Trump returns to Pennsylvania on Wednesday to headline a Fox News town hall.

The Sean Hannity-moderated prime time event is being held at the New Holland Arena in Harrisburg, the capital city of the key battleground state in the race between Trump and Vice President Kamala Harris.

Trump was most recently in Pennsylvania last Friday at a rally in Johnstown, in the western part of the state.

FOX NEWS TOWN HALL WITH FORMER PRESIDENT TRUMP MODERATED BY SEAN HANNITY - WEDNESDAY 9PM ET

Republican presidential nominee former President Donald Trump speaks during a rally at 1st Summit Arena at the Cambria County War Memorial, in Johnstown, Pennsylvania, on Friday, Aug. 30, 2024. (AP Photo/Rebecca Droke)

"Sixty-seven days from now, we're going to win Pennsylvania," the former president declared.

Harris stopped in Pittsburgh on Monday to team up with President Biden at a Labor Day event in the state's second-largest city and union stronghold. The vice president returns to Pittsburgh on Thursday for her second stop this week.

Fox confirmed that Harris is heading back to Pittsburgh to prepare for next week's first and potentially only presidential debate with Trump. Harris is expected to stay in the state through next Tuesday's prime time debate, which is taking place in Philadelphia.

MARGIN OF ERROR RACE BETWEEN HARRIS, TRUMP, AS CAMPAIGN ENTERS FINAL STRETCH 

While Election Day on November 5 is nine weeks away, early voting in Pennsylvania begins this month, as Harris noted on Monday, telling supporters that "ballots in Pennsylvania will start dropping in 14 days."

Democratic presidential nominee Vice President Kamala Harris and President Biden arrive at a campaign event at the IBEW Local Union #5 union hall in Pittsburgh on Labor Day, Monday, Sept. 2, 2024. (AP Photo/Jacquelyn Martin)

Pennsylvania is one of seven swing states that decided the 2020 election between Trump and Biden, and that both campaigns see as the states that will determine the outcome of the 2024 presidential showdown.

"It's the one state that it's hard to see someone losing and then still winning the presidential race," Pittsburgh-based longtime Republican national strategist and ad maker Mark Harris told Fox News. "It's clearly ground zero."

Mark Harris, a veteran of multiple GOP presidential campaigns, said, "You can see that in media reservations and in the candidates' travel schedules. Clearly, the Trump campaign and the Harris camp believe this is a must-win situation."

Mike Butler, a Pittsburgh-based Democratic consultant, told Fox News that when it comes to the White House race, "I don't think any other state quite swings the needle as much as Pennsylvania."

BIDEN TEAMS UP WITH HARRIS AS HE RETURNS TO CAMPAIGN TRAIL FOR FIRST TIME SINCE ENDING RE-ELECTION BID

The campaigns and the deep-pocketed super PACs supporting Harris and Trump have already shelled out over $336 million to run ads in Pennsylvania, according to data from the nationally known ad tracking firm AdImpact. That includes nearly $150 million to reserve air time to run spots in the final two months – a figure that is likely to rise in the coming weeks.

It is not just the top of the ticket campaigning in Pennsylvania. Minnesota Gov. Tim Walz, the Democrats' vice presidential nominee, campaigns Wednesday and Thursday in Lancaster, Pittsburgh and Erie. Sen. JD Vance of Ohio, Trump's running mate, has made campaign stops in Pennsylvania nearly every single week since becoming the GOP vice presidential nominee in mid-July.

GOP running mate Sen. JD Vance criticizes Vice President Kamala Harris and Minnesota Gov. Tim Walz at a Trump campaign event in Philadelphia on Aug. 6, 2024. (Fox News - Paul Steinhauser)

Pennsylvania, along with Michigan and Wisconsin, are the three Rust Belt states that make up the Democrats' so-called "Blue Wall."

The party reliably won all three states for a quarter-century before Trump narrowly captured them in the 2016 election to win the White House.

Four years later, in 2020, Biden carried all three states by razor-thin margins to put them back in the Democrats' column, as he defeated Trump.

Fast-forward to the present day, and Pennsylvania remains a jump-ball, as the latest public opinion surveys in the state indicate a margin-of-error race between Harris and Trump. 

"It's going to be fight to the finish. I think Trump has some advantages," Mark Harris said. "But its definitely going to be a very tight race."

Butler noted that Pennsylvania's had razor-thin margins in the past two presidential elections. "Trump's numbers are pretty solidly baked in. I can't see him faring any worse than he did the last two times, which means it's going to be a very competitive state," he said.

Get the latest updates from the 2024 campaign trail, exclusive interviews and more at our Fox News Digital election hub.