According to the NBC News tracker, more than 46 million Americans cast ballots for the 2024 election on Tuesday morning, accounting for more than a quarter of the expected electorate.

Both nominees, Vice President Kamala Harris and former President Donald Trump, have encouraged voters to get to the polls as soon as possible.

With a week left until the Nov. 5 election, early voting is underway in all seven battleground states, along with dozens of others. Social media has already seen reports of hours-long lines outside polling stations as voters flood the limited number of municipal spaces set up to allow early voting.

While millions of Americans have lined up to cast their votes in person, another 20 million Americans have mailed in their ballots. According to the University of Florida Election Lab, the 46.5 million early votes are almost evenly split between votes cast in person and votes cast by mail.

Some states, such as the key presidential battlegrounds of North Carolina and Georgia, have reported their early voter turnout setting records this election cycle.

In North Carolina, 353,166 ballots were accepted on the first day of early voting on Oct. 17, surpassing the record set by the first day of 2020, preliminary data from the State Board of Elections shows. More than 2.7 million votes had been cast across the state as of Tuesday, according to NBC News.

Georgia also broke its first-day early voting record with an estimated 310,000 ballots cast on Oct. 15. As of Tuesday, just under three million ballots had been received.

These historic voter numbers test the limits of America’s early voting infrastructure, which functions with only a fraction of the workers and polling places that will be open on Election Day.

Early voting is intended to provide Americans with more convenient alternatives to casting their ballots on Election Day. In some states, early voting can also give election officials a head start on processing or counting votes, allowing the burden of counting votes to be spread over several days.

Election and voting laws are set by individual states, not the federal government. This creates a patchwork of election operations across the country, each with its own rules.

For example, Arizona, Michigan and Nevada may begin counting their ballots before November 5. But in Georgia, Wisconsin and Pennsylvania, counting may not start until Election Day.

Early votes made up about two-thirds of votes cast in the 2020 election, according to the Associated Press.

This massive total, more than 100 million votes, was largely determined by the unique effects of the Covid-19 pandemic on American civic life.

While early voting data can provide useful clues about early patterns within the electorate and voter enthusiasm, they are not a predictive measure of Election Day outcomes.