Pennsylvania law allows counties to start pre-canvassing mail-in ballots at 7 a.m. on Election Day when the polls open.

However, Mercer County is counting absentee ballots starting Wednesday morning. 

"The state office is aware that we are counting on Wednesday, even though they want us to count on Tuesday but the state office has not reached out to us yet," said, Thad Hall the Director of Mercer County Voter Registration and Election Bureau.

"On Wednesday, we will start the process of canvassing mail-in and absentee ballots.  It is never a good idea to overlap these processes if at all possible; doing so opens a jurisdiction up to making mistakes because you cannot focus necessary resources on either task.  We will be accounting for every mail-in ballot, by precinct, and doing so in a structured and deliberate process.” said Hall

Pre-canvassing includes opening ballot envelopes, removing inner envelopes and ballots and scanning the ballots.

At 8 p.m. when the polls close, counties may begin to record and publish the counts, which is what Mercer County will be doing with in-person ballots. 

"The outcome of Tuesday's election could well depend on Pennsylvania. It is vitally important that the more than 3 million ballots cast by mail here be counted as soon as possible," Secretary of State Kathy Boockvar said. "The country will be looking to Pennsylvania for accurate and timely results."