That widely held opinion has made daily campaign visits the norm. Biden has stumped here more than in any other state by far, touching down in every media market, from an old steel town in the southwest to the central Pennsylvania dairyland to the big, bustling, colorful city of Philadelphia. Trump barnstormed across the state this week, hitting three campaign events across 200 miles in one day, from Eagles to Steelers country. Both candidates will be back in the state over the weekend and on Monday.

Here’s a Pennsylvanian’s look at the places Trump and Biden have been campaigning — and the reasons why those cities and towns are so critical in determining who wins the state’s 20 electoral votes.

Erie

Democratic Lt. Gov. John Fetterman repeats the words like a mantra: “Tell me who wins Erie, I’ll tell you who wins Pennsylvania.”

The little-known county might be the biggest bellwether in the state: In 2016, it went for Trump by only 2 percentage points.

Located in the state’s northwestern corner, Erie is a predominantly white, blue-collar area that was once a Democratic stronghold with a proud labor tradition. Four years ago, it flipped to Trump after supporting President Barack Obama twice. But in the 2018 midterms, it came home to Democrats in a major way, backing the party’s gubernatorial and Senate nominees by double digits.

After state elected officials lobbied Biden’s campaign for months to visit the area, the former vice president traveled there in October. At a plumbers union training facility, he leaned into class war rhetoric: “If every investment banker in New York went on strike, nothing would much change in America. But if every plumber decided to stop working, every electrician, the country would come to a halt.”

Trump made a swing in the county days later, getting headlines for joking that he was so confident in his position here that “before the plague came in, I had it made — I wasn't coming to Erie.”

The county is being seriously contested by both campaigns this year. Jim Wertz, chair of the Erie Democratic Party, took the task so seriously that he hired a field director in July. He even canvassed voters when Biden’s team abandoned the practice of door-knocking over the summer due to the coronavirus.

“If I was just going to judge this on voter turnout, mail ballots, face-to-face alone, I would feel pretty confident right now,” he said of the state of the race here. “But there’s so much scrutiny on the mail ballot process and there are so many unknowns about what Election Day is going to look like at the polls, that’s what bothers me. That’s what I think tightens the race.”

GOP Rep. Mike Kelly, whose district includes Erie County and more conservative areas nearby, likewise said on a recent call with reporters that feels “strong” about Trump’s position. But Kelly also inadvertently revealed a warning sign for Trump in Erie: He said the president is winning his congressional district in internal polls by about 10 percentage points — compared to 20 points in 2016.

Northeastern Pennsylvania

Luzerne and Lackawanna counties are next-door neighbors in northeastern Pennsylvania that did a lot to deliver the state to Trump in 2016.

The president flipped Luzerne, a declining historic coal region, carrying the county by 26,000 votes — about 60 percent of his margin of victory statewide. And while Hillary Clinton won Lackawanna, she only did so by fewer than 4,000 votes, down from nearly 27,000 by Obama in 2012.

Lackawanna, the smaller of the two counties, is home to Scranton, Biden's birthplace and the key to his middle-class political identity. So it’s no wonder that both Trump and Biden have made the area a priority, with the candidates making a combined total of five visits here this year.

When Biden announced a key plank of his economic recovery plan, he chose to do it from a metalwork plant in Lackawanna County’s Dunmore. Trump went to Scranton for a Fox News town hall in March. He also needled Biden by traveling to Old Forge, a 15-minute drive from Scranton, during the Democratic National Convention. And Trump is headed to Luzerne for a rally on the eve of the election.

“If Biden is elected, all of the security will quickly vanish, control of the border will be ceded to violent cartels and the left-wing crazies who empower them,” he said at the Old Forge rally, returning to the anti-immigration rhetoric he leaned into in 2016, which was popular in this region.

Northeastern Pennsylvania is one of the places where Trump is mining for even more votes than he won in 2016. The Republican National Committee said it has spent $350 million to revamp its national data program and locate pro-Trump voters who didn’t come to the polls four years ago.

A recent Muhlenberg College/Morning Call poll found Trump performing better in the northeast than any other part of the state, leading Biden 55-39 here.

“The turnout on Election Day is going to be in favor of Donald Trump and it’s going to come out huger than 2016,” said Justin Behrens, chair of the Luzerne County Republican Party.

Biden’s team, meanwhile, is mostly looking to narrow its losses in Luzerne and perform better in Lackawanna than Clinton, in part by using his hometown appeal.

“I think that Joe Biden is doing well in this area,” said Rep. Matt Cartwright, a Democrat whose district includes Scranton. “People know him and they know who he is: that he cares about people.”

Philadelphia and its suburbs

There’s no doubt that Biden will sweep Philadelphia and its surrounding suburbs. The question is by how much.

In another era, Montgomery, Chester, Delaware and Bucks counties were the state’s bellwethers in presidential races and reliable sources of Republican votes. Nowadays, the college-educated, well-off and increasingly diverse suburbs are becoming bluer and bluer with every passing election.

In the 2018 midterms, the Delaware Valley region helped Democrats pick up two House seats. And though turnout is usually down in off-year elections, three of Philly’s suburban counties delivered even more votes to Democratic Gov. Tom Wolf in 2018 than they gave to Clinton.

Biden’s campaign aims to run up the score in this treasure trove of Democratic votes, while Trump is trying to tamp down enthusiasm for his opponent and look elsewhere to make up for his deficit in southeastern Pennsylvania. The president’s campaign tactics — which include dispatching an army of poll watchers — has Democrats warning of outright voter intimidation.

Former Rep. Lou Barletta, a top Trump ally in the state, said Trump needs to outpace his 2016 performance in the more Trump-friendly parts of the state in order “to overcome some of the suburbs in Philadelphia and Pittsburgh.”

Bob Brady, the longtime chair of Philadelphia’s Democratic Party, thinks that Biden will pull more votes out of the state’s largest city than Clinton. “People know that he’s doing a horrible job, and I think more people will come out to vote him out,” he said of Trump.

But some Black and Latino leaders in the city have raised alarms: They report that excitement among young African American men for Biden is lagging, and Hispanic voters are returning their mail ballots at lower rates than others.

Biden has stumped in Philadelphia, as well as in Delaware and Bucks counties — in some cases, multiple times — slamming Trump for botching his management of the Covid-19 pandemic. He also dispatched his most effective surrogate, former President Barack Obama, to Philly in part to speak directly to Black men. And Biden will be back in the city on Sunday.

Trump — who infamously said, "Bad things happen in Philadelphia,” during one of the debates — also made a stop in the city in September for an ABC town hall. And he is campaigning in Bucks, the collar county where he performed best in 2016, on Saturday.

Johnstown

While rolling through Pennsylvania in September on an Amtrak whistle-stop tour this year, Biden got off at a struggling former steel town in the southwestern part of the state.

His pitch was aimed directly at the working-class white voters of Johnstown who broke hard toward Trump in 2016.

“If Trump and his Park Avenue pals start paying their fair share, we’ll have more than enough money to finally build an economy that works for everyone," he said. "So I promise you this, I see you. I hear you. I respect you. I grew up with you.”

Southwestern Pennsylvania is to Trump what the Philadelphia region is to Biden: Outside of Pittsburgh’s Allegheny County, it’s Trump Country. But margins matter — and Biden is trying to cut into the amount by which Trump wins here.

Trump’s aides, meanwhile, are certain that they’ll be able to find even more supporters in this part of the state who simply didn’t go to the polls in 2016. They point to big voter registration gains they’ve made in places like Cambria County, where Johnstown is located: They’ve added nearly 8,000 net Republicans to the books here since 2016, while Democrats have lost more than 7,000.

The region is so important to Trump’s campaign that about one-third of his visits to the state this year have been to southwestern Pennsylvania. He’s not finished: He’ll be in Butler County Saturday.

His team believes it has a winning message for the area: In the closing days of the race, it has been hammering on the point that Biden is hostile to fracking, a technique for drilling natural gas that triggered an economic boom in western Pennsylvania. Biden, with an eye toward preventing a Trump blowout in the region, has repeatedly gone out of his way to say that he will not ban fracking.

At a rally in Johnstown, the president’s first stop in the state after he recovered from Covid-19, Trump accused Biden of being a fossil fuel job-killer. “They will lose, and you will lose, Pennsylvania a million jobs,” he said. “With me, you’re going to frack.”

Lancaster

Lancaster, home to scrapple, dairy farms and the state’s Amish community, has long been a Republican bastion. In 2016, it supported Trump by 19 percentage points.

But it is diversifying and ever so slowly becoming more Democratic. In 2000, 62 percent of voters were registered Republican and only 25 percent were Democrats. Today, it’s 51 percent to 23 percent.

As one of the biggest counties in the state, Biden stopped in Lancaster twice this election season, for a roundtable focused on the Affordable Care Act and for a Labor Day event with union workers. He talked about his role in the Obama administration overseeing stimulus funds that helped plug gaps in state government.

For Biden, the goal isn’t necessarily winning here but rather chipping into Trump’s lead. During the midterms, Democratic Sen. Bob Casey narrowed his Republican opponent’s margin of victory to only 8 points — and Wolf, who hails from neighboring York County, lost by only 3.

For Trump, the goal is to maintain his commanding 2016 performance or, in the best-case scenario, find even more voters here. That’s why the president held a rally in Lancaster the week before Election Day, boasting that the “Pennsylvania Dutch are voting en masse.” If true, that would be a departure: the Amish community typically votes at low rates. Trump also attacked Biden for supporting trade deals that he said hurt American workers and painted him as hostile to the state’s fracking industry.

Allegheny County

Home to Pittsburgh, the second biggest city in the state, Allegheny County is another tranche of Democratic votes. The city is also surrounded by well-educated, wealthy suburbs where Democrats like their chances.

Just as in Philadelphia, Biden is trying for a wipeout here while Trump’s best hope is to dial down Democratic excitement. In 2016, Clinton pulled about 15,000 more votes out of Allegheny County than Obama did four years prior.

Pittsburgh was a part of Biden’s whistle-stop train tour through western Pennsylvania.

The former vice president also gave a major speech here in August, where he pushed back on Trump’s claims that he is soft on rioters and looters in big cities — the most full-throated rejection of the GOP’s attacks on him over civil unrest up to that point. And his first 2019 rally was in Pittsburgh.

While on the western side of the state, Biden also took the opportunity to make the case that he’s not opposed to the natural gas industry: “I am not banning fracking.”

Trump stumped in September in Allegheny County’s Moon Township, which he won in 2016. “Your steel mills would — every one of them would have been gone had I not won,” he told rallygoers.

And he sounded a confident note, despite trailing Biden in nearly every state poll taken here since June: “We’re going to win Pennsylvania.”