Biden held his first of two rallies in Pittsburgh, delivering an altered version of his stump speech that focused more forcefully on his pitch to the African American community, and criticism of the president’s treatment of the group.

He expanded his pitch to Black and brown voters, talking about the importance of Black businesses to systemic racism and Trump’s claim that he has been the best president for Black America since Abraham Lincoln.

“Honk if you think his commitment of having done more for the African American community that  Abraham Lincoln is true? Honk your horn,” Biden said and getting silence in return.

“You got it, man, Pittsburgh. Honk if you think it's a bunch of malarkey,” he said and was answered with a chorus of honks.

Biden’s pitch to black voters is one of his lengthier set of remarks about African American issues.

In Miami, former President Barack Obama made another impassioned plea for Americans to head to the polls and made another stinging indictment of Trump's four years in office.

“After four years of failure and division, we have the power to change America. Tomorrow, you can put an end to the politics that tries to pull us apart, just to win the election," he said.

"Florida, you delivered for me twice. And now I'm asking you to deliver for all of us, and elect Joe Biden and Kamala Harris as the next president and vice president of the United States of America,” he added.

-ABC News' Molly Nagle and John Verhovek

There's a good chance we won't know who won the presidential election on election night.

More people than ever are voting by mail this year due to the pandemic, and mail ballots take longer to count than ballots cast at polling places. But because each state has its own rules for how votes are counted and reported, some will report results sooner than others.

Those disparate rules may also make initial returns misleading: The margins in some states may shift toward Democrats as mail ballots -- which are overwhelmingly cast by Democrats -- are counted, while states that release mail ballots first may experience a shift toward Republicans as Election Day votes are tallied.

FiveThirtyEight compiled a complete guide to poll closing times, vote counting and races to watch on election night.

-FiveThirtyEight's Nathaniel Rakich and Elena Mejia

Biden and Lady Gaga, who is performing tonight at his drive-in rally in Pittsburgh, visited the University of Pittsburgh to greet supporters and student organizers.

They each thanked the volunteers for their hard work, with Biden adding his praise for the young supporters.

"Thank you, thank you, thank you for all you're doing for us. By the way, you are the most incredible generation there is. For real. Z Generation and all -- all kidding aside, you're the best educated, you're the brightest, you're the least prejudiced, you're the most engaged and most open generation in American history. That's why we're counting on you," Biden said.

The Democratic nominee also joked about their joint event later, telling volunteers, "Lady Gaga's gonna be speaking and I'm gonna be singing."

-ABC News' Molly Nagle

In his second rally of the day and his last in the all-important battleground state of Pennsylvania, the president exuded confidence about winning Pennsylvania, declaring, "This does not look like a second-place finish.

"You know, we win Pennsylvania, we win the whole deal. You know that, right? Just like last time. We want to have the same result as we had last time," Trump said, though a new ABC News/Washington Post poll puts Biden with a narrow lead in the state Trump won by just one point in 2016.

As accustomed, Trump also went after Pennsylvania Gov. Tom Wolf, a Democrat, for having restrictions in place to prevent the spread of COVID-19, as cases and hospitalizations rise in the state.

"Pennsylvania, get your state open. Get it open. Terrible. Terrible. Your governor has to open your state, Pennsylvania, has to open your state," Trump said to chants of "Lock Wolf up."

He went on to address counting ballots in Pennsylvania -- after GOP efforts to stop mail-in ballots from being counted after Election Day were blocked last week -- and in a somewhat threatening tone said, "We have a lot of eyes on the governor" and "we got a lot of powerful eyes watching them."

"So governor, open your state and please, don't cheat, governor. Please don't cheat. Because we're all watching. We're all watching you, governor. We got a lot of -- we have a lot of eyes on the governor and his friends. A couple of other governors out there too," Trump said.

The president may have been talking about poll watchers or attorneys, but he didn't explicitly specify.

-ABC News' Terrance Smith, Will Steakin and Ben Gittleson