However, over the next few days, Biden greatly closed the margin due to outstanding votes from Democratic-leaning areas, most notably Philadelphia and Pittsburgh, as well as mail-in ballots from all parts of the state which strongly favored him.
On the morning of November 6, election-calling organization Decision Desk HQ forecast that Biden had won Pennsylvania's 20 electoral votes, and with them the election.
[6] The following morning, November 7, at the same time that the Trump campaign was holding a press conference outside of a Philadelphia landscaping business,[7] nearly all major news organizations followed suit and called Pennsylvania for Biden, proclaiming him president-elect.
At the same time, he reclaimed two of the three large industrial counties which had voted Democratic for at least six consecutive elections before Trump flipped them in 2016: Erie and Northampton.
Biden became the first Democratic candidate running for president to garner at least 100,000 votes in the Republican stronghold county of Lancaster.
With Ohio, Florida, and Iowa backing the losing candidate for the first time since 1960, 1992, and 2000 respectively, this election established Pennsylvania, Wisconsin, and Michigan as the states with the longest bellwether streak still in effect today.
Biden became the first Democrat to win the White House without carrying Luzerne County since Harry Truman in 1948.
This was in response to President Trump's skepticism of the practice, expressing concern mail-in voting may result in voter fraud that would potentially benefit the Democratic Party.
Counties that flipped from Republican to Democratic Biden and Trump both won half of the 18 congressional districts in Pennsylvania,[203] including each winning one held by the opposite party.
From the Civil War on, it has generally had a partisan lean; during the Third and Fourth Party Systems, Pennsylvania was a classic Yankee Republican state.
As in Michigan and Wisconsin, Biden ran behind Barack Obama's performances in 2008 and 2012, though he received more votes total in the state this cycle due to record-breaking turnout.
As for Trump, he easily set the record for total number of votes for a Republican candidate in Pennsylvania history (as with Biden, largely due to record-breaking turnout).
Before 1992, all three had been Republican strongholds in the state, and Chester had been considered a swing county as recently as 2012, when Romney narrowly carried it, but all three have drifted towards the Democratic column, as they tend to be socially liberal.
Trump maintained much of his momentum throughout rural and industrial Pennsylvania from four years earlier, with convincing victories in counties that were once competitive or even Democratic-leaning.
[212] Other previously competitive counties that Trump performed well in included Berks and Cambria, both of which voted for Obama in 2008.
[214] On November 24, 2020, the Secretary of the Commonwealth of Pennsylvania, Kathy Boockvar, certified the results, and Governor Tom Wolf, in accordance with the law, signed the certificate of ascertainment for the Biden/Harris slate of electors for Biden and Harris and sent it to the Archivist of the United States.
[216][217] On November 25, 2020, the Pennsylvania Senate Majority (Republican) Policy committee held a public hearing regarding the counting of ballots in this election.
[225] On January 6, 2021, as Congress certified the Electoral College results confirming President-elect Joe Biden and Vice President-elect Kamala Harris as the winners, there was an objection to Pennsylvania's 20 electoral votes, brought forward by U.S. Representative Scott Perry of Pennsylvania's 10th congressional district and officially signed onto by U.S.