Voters in the northern hamlet of Dixville Notch braved freezing cold to uphold the town's 40-year-old tradition of being the first in the state to announce its election results.
All 26 registered voters in Dixville Notch - 15 Independents and 11 Republicans - cast their ballots in wooden voting booths in a cramped room at a resort in the northern White Mountains.
The Republicans voted for President George Bush.
"I'm grateful to be here and for the support here at Dixville Notch. This is a big step for me," said Clark, who is making his first attempt for any elective office.
Dean falls behind
Massachusetts Senator John Kerry got three votes while two ballots were cast for North Carolina Senator John Edwards.
Clark (R) has won wide support
from veterans in the country
One each went to Connecticut Senator Joe Lieberman and former Vermont governor Howard Dean.
Right at midnight, Rick Erwin, an Independent, kicked off the primary vote, casting his ballot for Clark.
"I've been leaning that way. I like everything he said about the environment and the economy," Erwin said.
Erwin also said Clark was very strong on foreign policy.
Clark made a big push in New Hampshire to woo Independents, a segment which includes many veterans and tends to reward
plain-speaking non-conventional candidates.
A Reuters/MSNBC/Zogby poll released on the eve of the primary had Clark in third place behind front-runners Kerry and Dean.
Dixville Notch takes advantage of a state election law that allows communities to close the polls after all registered voters have cast their ballots.
Clark and wife Gert take questions
from the media after the vote
Every four years, Dixville Notch, for a moment, becomes the centre of the US presidential campaign because it represents the first direct vote for a candidate.
In the Iowa caucuses a week earlier, voters chose delegates for the candidates.
Dixville Notch generally is referred to by political pundits as a tiny hamlet, but in reality it is the home of the 15,000-acre Balsams Resort.
In 1960, in an effort to get some publicity as well as serve a civic function, the resort's late owner, Neil Tillotson, opened voting booths at midnight on primary day and reported the results of the staff's ballots to the local wire service.
The same procedure was followed on election day. Every four years since, the media has turned to Dixville Notch for the nation's first votes.