Democratic presidential candidate Sen. Bernie Sanders (I-Vermont), at a rally, August 10, 2015, in Los Angeles. AP US Sen. Bernie Sanders (I-Vermont) has surged to a lead over Democratic presidential front-runner Hillary Clinton in the first-in-the-nation primary state of New Hampshire, according to a new Franklin Pierce University/Boston Herald poll out late Tuesday night.

The poll gives Sanders a 44-37 lead over Clinton in the run for the Democratic nomination in the state.

It signals that Clinton will face a tougher-than-expected challenge in the important first-primary state, as voters in the Granite State remain unenthusiastic about her candidacy.

According to the poll, just 35% of New Hampshire Democratic voters said they are "excited" about Clinton's campaign. And 38% of Democrats have a "very favorable" impression of Clinton (though eight in 10 Democrats do view her favorably in general).

All of Clinton's numbers have plunged significantly since March, when Franklin Pierce University last surveyed the Granite State. In March, 50% of Democratic voters in the state viewed her "very favorably."

And Clinton held a 25-point lead in the state in the March poll over Sen. Elizabeth Warren (D-Massachusetts), who is not running for president. Sanders garnered just 8% of the vote in March. Meanwhile, more than half of New Hampshire Democrats have a "very favorable" impression of Sanders, who has been seeing swelling crowds at events across the nation.

The poll grabbed the attention of many political analysts as a fresh sign of Clinton's potential weaknesses as a candidate.

"Clinton is in free fall, and leaders of the party agree that Sanders would lose at least 49 states in the general election," said Greg Valliere, the chief political strategist at the Potomac Research Group. "So the speculation will intensify — starting today — that Joe Biden may have to save the party from a debacle."

Biden, who will soon make a decision about running, grabs 9% of the Democratic vote in New Hampshire. According to the poll, 46% of New Hampshire Democrats said they want him to enter the race, while 42% want him to stay out. His favorability ratings have increased by 14 points since March among Democratic voters, according to the poll.

US Vice President Joe Biden next to then Secretary of State Hillary Clinton at a State luncheon in Washington, October 13, 2011. REUTERS/Yuri Gripas

The poll's release comes as Clinton is preparing to hand over to federal authorities her private email server and thumb drive of work-related emails from her time as secretary of state, an unexpected move in an attempt to quash the burgeoning controversy.

Clinton remains the overwhelming front-runner in both national polls and surveys of Iowa, which holds the first caucuses next year. According to a Real Clear Politics average of recent national polls, she leads by an average of more than 35 points nationally and more than 25 points in Iowa.

The Boston Herald/FPU poll, which was conducted from August 7-10, has a margin of error of plus-or-minus 4.7%.