Pennsylvania is always a mess on election night. Honestly, if you were watching the returns back in November 2020, you probably remember that weird, sinking feeling as the "red mirage" stayed on the screen for days. It looked like a blowout at first. Then, the mail-in ballots from the 67 Pennsylvania counties 2020 election maps started trickling in.
Everything flipped.
It wasn't just magic or a sudden change of heart. It was math. Specifically, it was the way different counties handled their piles of paper. While the national media focused on the big cities, the real story was happening in the "collar" counties and the industrial centers that had started to drift away from their traditional roots.
The Suburbs That Swung the State
People love to talk about Philadelphia. But if you actually look at the data, Joe Biden’s share in Philly actually dropped a tiny bit compared to Hillary Clinton in 2016. He got about 81% there, while she had around 82%.
The real movement? The suburbs.
The "Big Four"—Montgomery, Bucks, Delaware, and Chester—basically handed Biden the keys to the Commonwealth. Take Chester County. It used to be a reliable Republican stronghold. In 2020, it saw an eight-point shift to the left. Biden ended up winning it by over 17 points. That is a massive swing for a place that Mitt Romney actually won just eight years earlier.
In Montgomery County, the numbers were even more staggering. Biden netted 40,000 more votes there than Clinton did. Think about that. One single county provided nearly half of his total statewide margin of victory, which ended up being roughly 80,500 votes.
- Montgomery: Biden +131,000 margin
- Delaware: Biden +86,000 margin
- Chester: Biden +57,000 margin
- Bucks: Biden +17,000 margin
When you add those up, the "collar" was a blue wall that Donald Trump simply couldn't climb over, despite his massive gains in the rural "T" section of the state.
Why the "Red Mirage" Was So Dramatic
We have to talk about the counting process because it’s why everyone was so stressed. Pennsylvania law at the time (and still, mostly) prohibited counties from processing mail-in ballots before Election Day.
In-person votes were counted first. Those skewed heavily Republican.
The mail-in ballots? Those were about 75% Democratic.
This created a literal timeline of anxiety. In Allegheny County (home to Pittsburgh), the tallying took days. Because Biden won the mail-in vote so decisively, he was able to erase a half-million-vote deficit as the week ground on. By the time the dust settled, Biden had 3,458,229 votes (50.01%) to Trump’s 3,377,674 (48.84%).
The Industrial Boomerangs and Holdouts
Not every blue-collar area went the same way. This is where the Pennsylvania counties 2020 election story gets nuanced.
Biden managed to "boomerang" two major counties back into the Democratic column: Erie and Northampton. These are the ultimate bellwethers. If you win Erie, you usually win the state. Trump flipped it in 2016, but Biden took it back by about 1,400 votes. It was razor-thin.
Then there’s Luzerne County. This place is fascinating. It used to be a Democratic fortress. Trump won it in 2016 and held it in 2020. Even though Biden grew up nearby in Scranton (Lackawanna County), he couldn't flip Luzerne back. However, he did manage to slow the bleeding there. Trump won it, but by a slightly smaller margin than people expected given the registration trends.
A Surprising Stat in Lancaster
You’ve probably heard that Lancaster County is deep red. It is. But 2020 saw something historic. Biden became the first Democrat to ever get more than 100,000 votes in Lancaster. He hit 44% of the vote there—the best showing for a Democrat since Lyndon B. Johnson in 1964.
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Rural Dominance and the Registration Shift
While Biden was making inroads in the suburbs, Trump was running up the score in the "T"—the central and northern parts of the state. In counties like Cambria and Bedford, the GOP margins were historic.
Since 2015, Republicans have been chipping away at the Democratic registration advantage. It used to be nearly a million-voter lead for Democrats. Now? It’s narrowed significantly. In 64 out of 67 counties, Republicans have netted more registered voters over the last decade.
The only exceptions? Chester, Delaware, and Montgomery. This creates a sort of "two Pennsylvanias" dynamic. You have a massive, deep-red geographical area that is getting redder, and a few high-population suburban hubs that are getting bluer and essentially canceling out the rest of the map.
What This Means for Future Elections
Looking back at the Pennsylvania counties 2020 election results, the most actionable insight isn't about who won, but where the floor is for both parties.
- Watch the 40% Mark: If a Democrat can hit 40% in a place like Cumberland or Lancaster, they are likely winning the state. These "pink" counties are the real battlefield.
- The Mail-In Factor: Mail-in voting is here to stay. In 2020, over 2.6 million Pennsylvanians used it. It changed the "shape" of the election from a one-day event to a month-long process.
- Registration Trends: Keep an eye on the Department of State’s weekly registration reports. If the GOP continues to flip registered Democrats in western PA, the Democrats' suburban gains will eventually be neutralized.
If you want to understand PA politics, stop looking at the state as a whole. Look at the margins in Westmoreland. Check the turnout in the Lehigh Valley. The 2020 data shows us that Pennsylvania isn't one state; it’s a collection of 67 different stories that just happen to share a border.
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For anyone looking to dive deeper, your next move should be checking the Official 2020 General Election Returns on the Pennsylvania Department of State website. They provide a precinct-by-precinct breakdown that shows exactly how neighborhoods within these counties split—often showing that even "blue" counties have deep-red pockets and vice versa.