Sen. Bernie Sanders (I-Vt.) speaks at the David Lawrence Convention Center in Pittsburgh about the health-care issues surrounding a Senate vote to repeal the Affordable Care Act in June. (Jeff Swensen for The Washington Post)

An early poll of the 2020 Democratic primaries, which kick off in roughly 820 days, finds Sen. Bernie Sanders (I-Vt.) at the front of a crowded field — in a race that would bear little resemblance to 2016’s two-candidate marathon.

The first 2020 Granite State poll, conducted by the University of New Hampshire’s survey center, finds that 31 percent of the state’s Democrats would back Sanders if the first presidential primary were held today. Twenty-four percent would back former vice president Joe Biden, while 13 percent would back Sen. Elizabeth Warren (D-Mass.). No other contender, not even Facebook founder Mark Zuckerberg, cracks double digits.

Sanders, who won the 2016 New Hampshire primary by a historic landslide, has also spent more time in the state than any potential rival. Later this month, he’ll headline a Democratic event in coastal Strafford County; last month, he headlined two of the party’s Labor Day events.

Rep. John Delaney (D-Md.) and Los Angeles Mayor Eric Garcetti, who have also appeared in New Hampshire this year, registered no support in the poll. (Delaney is the first, and so far only, declared Democratic candidate.)

Still, the recent history of UNH’s poll suggests that ultra-early numbers are largely academic. Four years ago, the Granite State poll pegged former secretary of state Hillary Clinton at 64 percent in New Hampshire. Six percent of voters supported Biden, and another 6 percent supported Warren — neither of whom ended up in the race.

The pollsters did not ask about Sanders until July 2014, after he had made several visits to the state. In that survey, Clinton came in at 59 percent; Sanders, at 5 percent. The Vermont senator did not run close to Clinton until July 2015, when both were official candidates and after Clinton had been damaged by her use of a private email server while at the State Department.

Clinton’s collapse and eventual defeat by Sanders was unprecedented in modern primary polling; so, however, was her early lead. Ahead of the 2008 primary, which Clinton ended up winning, no Democrat ever cracked 45 percent support in New Hampshire polls. The same was true in the crowded 2004 Democratic primary, when then-Vermont Gov. Howard Dean and then-Massachusetts Sen. John F. Kerry both enjoyed a home-field advantage in New Hampshire.