WASHINGTON (AP) — Get ready: Voting in the 2016 election is now underway.

Advance voting begins Friday in North Carolina, the first of 37 states that will allow balloting by mail for any reason or in person before the actual Election Day of Nov. 8.

It's part of a nearly nine-week campaign frenzy in which millions of voters will have the ability to fill out a ballot and be done with the 2016 presidential race.

North Carolina residents are first, and they can now submit absentee ballots by mail without an excuse. They also will be able to vote early at polling booths beginning Oct. 20.

Ballots from all 50 states will be sent to members of the armed services and voters living abroad the week of Sept. 19. And Georgia residents may also begin mailing in ballots that week, followed by battlegrounds Wisconsin and Virginia.

Iowa will accept early ballots starting Sept. 29, three days after the first presidential debate.

"If one campaign does significantly better in harvesting early votes, that campaign will have a substantial advantage as election day approaches," said Paul Gronke, a Reed College professor and director of the Early Voting Information Center in Portland, Oregon.

The stakes are high: Voters who cast ballots in advance are expected to make up between 50 to 75 percent or more of all ballots in the battlegrounds of North Carolina, Colorado, Florida, Nevada, Arizona and Georgia, according to data compiled by The Associated Press.

Nationwide, about 45.6 million people or roughly 35 percent of the electorate attracted by its convenience voted prior to Election Day in 2012, and that number is expected to increase in 2016.

The campaigns know it, too.

Hillary Clinton appeared in Charlotte, North Carolina, on Thursday and applauded a recent federal appeals court decision invalidating restrictions that the judges determined made it harder for non-whites to vote. "Get out and vote and make it clear we're not putting up with that," she said.

The Trump campaign, working with the Republican National Committee to boost absentee mail balloting in Florida, North Carolina, Ohio and Iowa, described its early efforts as key to a "path to victory."

"We must reach every voter before early voting and Election Day," wrote campaign manager Kellyanne Conway in a Sept. 5 memo.