New Hampshire Democratic Party Chairman Ray Buckley says his phone’s ringing off the hook with calls from likely White House contenders.

“There are so many potential contenders wanting to come up for our events, it’s just mind-blowing, the activity,” he told Fox News.

Several potential Democratic presidential candidates are making trips this weekend to the state that traditionally holds the first primary on the road to the White House -- part of a wave of hopefuls taking advantage of the expectation that Hillary Clinton, who kept young candidates on the sidelines last time, is politically finished.

One visitor is Julian Castro, who says he’ll decide whether he runs for the 2020 Democratic nomination after November’s midterm elections and before the end of this year.

“During the course of the next few months I’m going to get a sense of what people are thinking and also the reaction out there, and what’s important to the voters. And through doing that, I’m convinced that I’ll come to a decision as to whether I’m going to jump in or not,” the former San Antonio mayor and housing secretary in President Barack Obama’s administration said.

Castro delivers the commencement address Saturday at New England College in Henniker. It will be his second trip to New Hampshire this year.

The next day, Los Angeles Mayor Eric Garcetti gives a commencement speech at Southern New Hampshire University. Garcetti, who’s making his second trip to the Granite State since last summer, said “I don’t have a set timetable" when it comes to deciding on a presidential run. But he added "sometime in the first quarter of next year most would-be candidates should make the decision."

Also in the state this weekend is former Missouri Secretary of State Jason Kander, who’s making his whopping 11th trip to New Hampshire in the past year. Kander, who narrowly lost a 2016 bid for the U.S. Senate against GOP incumbent Sen. Roy Blunt, is the founder of Let America Vote, an organization that defends voting rights. He’ll headline the Rockingham County Democrats annual clambake.

And Rep. John Delaney of Maryland, who last summer declared his candidacy for the White House, pays a visit on Friday to the Puritan Backroom restaurant in Manchester, a must-stop for presidential contenders.

And that's just the beginning of the next wave in the 2020 procession, as Democrats excited about the prospect of taking on President Trump scramble to get their names in the mix -- and their faces before voters who play an outsize role in choosing nominees.

The following weekend, Rep. Tim Ryan of Ohio delivers the commencement addresses at the University of New Hampshire Law School. And Sen. Jeff Merkley of Oregon headlines a meeting of the Rockingham County Democrats.

And a figure at the center of much speculation, former Attorney General Eric Holder, plans to speak June 1 at the Politics and Eggs forum at the New Hampshire Institute of Politics, another must-stop for White House hopefuls.

Holder hasn't exactly squashed the speculation, either. Asked about his 2020 plans last month on MSNBC, Holder said: “I’m thinking about it but I’ve not made any determinations.”

There’s been a steady flow of potential contenders paying visits. Factor in the upcoming stops, and over the past year, 12 Democratic White House hopefuls will have made 38 trips to New Hampshire. And it’s not just the Democrats.

Two high-profile potential GOP primary challengers to Trump – Ohio Gov. John Kasich and Sen. Jeff Flake of Arizona – grabbed national media attention when they stopped in the Granite State earlier this year.

For the Democrats, four years makes a difference.

At this point in the last election cycle, the likely prospect of an eventual Clinton candidacy kept the field, and the early visits, to a minimum. There were only seven trips by four potential White House contenders during 2013 and the first half of 2014.

But with Clinton making clear she likely won’t run for public office again, and Trump’s presidency energizing Democrats across the country, the party may see its largest White House field and most wide-open race in nearly a generation.

With former President Barack Obama and the Clintons dominating party politics for a quarter century, “there has been a bottleneck for nearly a generation of up-and-comers to explore their future,” Buckley said.

“I think it’s a great thing that we have this entire new generation of folks that are thinking about it, exploring it,” he added.

While White House hopefuls are flocking to the Granite State this year, the biggest names in the potential field of candidates have so far stayed away.

It’s been a year since former Vice President Joe Biden trekked to New Hampshire, to headline the state party’s major fundraising gala. Former Democratic presidential candidate and Vermont Sen. Bernie Sanders hasn’t set foot in the state since last October, when he headlined a Strafford County fundraising dinner. And Sen. Elizabeth Warren of Massachusetts hasn’t visited since the 2016 campaign.

Blame midterm politics for some of the absences. Some potential 2020 contenders facing re-election this November may be hesitant to make the trip to the Granite State.

“Both Bernie and Elizabeth are up for re-election this year so we understand that,” Buckley said.

Buckley noted that the 2020 cycle reminds them of the early stages of the 2008 race for the Democratic nomination, when Obama outlasted Clinton in a marathon and historic battle.

Granite State-based Democratic consultant Jim Demers agreed.

“I think this is a lot like 2006. The two biggest names who ran, Obama and Clinton, did not come to New Hampshire until after the midterm elections,” said Demers, a former state representative who served as New Hampshire co-chair for Obama’s 2008 campaign.

“The candidates that were coming were the ones that were not as well known,” he explained.

Delaney fits that description.

Earlier this month Delaney, who has virtually no name recognition outside of his congressional district in Maryland, made his seventh trip to New Hampshire since launching his campaign.

Delaney said he’s going old school as he visits the early voting states, adding, “I am pursuing a bit of an old-fashioned strategy in some ways, which is meeting the voters.”