More than 58 million Americans have already voted

The last day to vote in the 2020 general election is Nov. 3. But ballots may not be counted for several days, if not weeks, after that date, experts said.

Due to an anticipated record amount of mail-in voting this election season, combined with ballot counts that won't start until Election Day in most states, election officials across the country could be overwhelmed in some cases.

Deadlines for receiving mail-in ballots also extend past Nov. 3 in several states, all but making it a given that votes will be recorded in the days or even weeks after the election.

"I buy that we're going to know quite a bit on election night … we could even get an election night call. Still, I would advise caution. If it does come down to the Midwest, we could be waiting for a long time," Nate Silver, editor-in-chief of FiveThirtyEight, said on ABC's "This Week" Sunday,

The issue of mail-in ballot receipt deadlines is also fraught with legal challenges -- some of which are still playing out in court with less than two weeks to go until the general election.

Despite these new complexities, experts are confident voters' ballots will be counted this election season.

Here's a general look at what it takes to tally up the votes of millions of citizens.

Air Force One touched down in New Hampshire a short time ago and was making its way over to the crowd of people waiting for the president's campaign rally.

Five individuals in Vice President Mike Pence's orbit have tested positive for the coronavirus, including his chief of staff Marc Short and political aide Marty Obst.

Devin O'Malley, press secretary for the vice president, announced Saturday in a statement that Short tested positive.

Sunday morning, multiple sources familiar with the matter told ABC News that in addition to an outside political ally of Pence's four of his staffers have tested positive. One senior-level source stressed that the three of the staffers have been quarantining since the middle of this past week.

O'Malley said both Pence and wife Karen Pence tested negative for the virus on Saturday and a pool report indicated they tested negative again on Sunday morning. The vice president is still expected to travel to North Carolina later on Sunday to speak at a rally in Kinston.

-ABC News' John Santucci and Katherine Faulders

ABC News Chief Justice correspondent Pierre Thomas said Russia appears to be "seeking direct access" to American voters to sow division and unrest.

Senior national security officials alerted the American public Wednesday that Iran and Russia have both obtained voter data in their efforts to interfere in the 2020 U.S. election.

Thomas said on ABC's "This Week" Sunday that those efforts appear to be aimed at creating problems before the election and possibly just after Election Day "if we don't quickly know a result."

On Friday, U.S. officials told ABC News that systems containing election-related information from two counties in two separate states were successfully hacked by the Russian effort. While the FBI and Cybersecurity and Infrastructure Security Agency have seen no evidence that data has been altered, FBI and Homeland Security officials expressed concern that Russia "may be seeking access to obtain future disruption options, to influence U.S. policies and actions, or to delegitimize SLTT government entities."

Iran is "aggressively pursuing the same goal," Thomas said Sunday.

Director of National Intelligence John Ratcliffe said Wednesday that Iran was separately behind a series of threatening emails that were found to be sent this week to Democratic voters, which he said was "designed to intimidate voters, incite social unrest and damage President Trump."

Alireza Miryousefi, spokesman for the Iranian Mission to the U.N., denied the allegations to ABC News.