More people have voted early or by mail than in any other presidential race in history, so it's anyone's guess how long it will take to tally ballots on this Election Day.
More than 100 million citizens have already made their choice, even as voters waited in line Tuesday to mark their ballot in a presidential election that is historic for myriad reasons: it occurs during a global coronavirus pandemic against the backdrop of a polarized country with deeply held beliefs.
In 11 states, early voting constitutes at least 90% percent of ballots cast in the entire 2016 election.
In 2008, Barack Obama was declared victorious when California polls closed at 11 p.m. EST. In 2012, a decision came just minutes later. In 2016, despite polls predicting Hillary Clinton would become the nation's first female president, Donald Trump had won North Carolina, Ohio and Florida by 11 p.m. About 1:30 a.m., Pennsylvania was called for Trump, and at 2:30 a.m., Wisconsin pushed him into an electoral victory.
And then there was the infamous 2000 election, when no winner was declared until the Supreme Court ruled in December.
So while we wait to find out whether President Donald Trump or Joe Biden will live in the White House come 2021, here's what to keep in mind on election night.
When do battleground states start counting?
Arizona began counting two weeks ago, and half the state's voters have already cast their ballots, making it likely a winner will be declared Tuesday night or early Wednesday.
Florida began counting 22 days ago, and 64% of registered voters have already made their choice, meaning all votes should be counted by election night, unless a recount is needed.
Pennsylvania, hotly courted by Trump and Biden in a razor-thin race, may not be called Tuesday night. Several counties have said they will not begin counting early votes until after the polls close, and Trump has already promised to file legal suits to throw out uncounted ballots.
North Carolina has been counting absentee ballots for the past five weeks. Election officials have said they fully expect to announce a winner election night since early voting has already surpassed voter turnout in the 2016 contest.
Wisconsin may take a while to announce a victor. The state is accepting absentee ballots until polls close at 9 p.m. Counting begins Election Day. Nonetheless, the governor has said results may be quickly known. "I believe that we will be able to know the results of the Wisconsin election, hopefully that night and maybe at the latest the very next day," Gov. Tony Evers said at an October briefing.
When do the polls close in key states?
In-person voting stops at 8 p.m. ET in Florida and Pennsylvania.
Texas polls close at 9 p.m. ET, as does voting in Michigan, Wisconsin, Arizona and Minnesota.
How to watch election coverage
CBS News will feature highlights and analysis on "Red & Blue" beginning at 5 p.m. ET. Continuous coverage begins at 7 p.m. with exit polls and up-to-the minute calls from the CBS News Decision Desk.
A CBS live blog can be seen here. Download the free CBS News app for full CBSN coverage and live updates. CBSN streaming is available on all major platforms, including: iOS, Android, Roku, Amazon, Apple, Samsung and Pluto.