Turnout was particularly high in Portsmouth and Keene -- both of which are overwhelmingly Democratic.
In a northern hamlet of the state, voters of Dixville Notch and Hart's Location cast the first 46 ballots of the primary season, giving wins to Obama on the Democratic side and Sen. John McCain of Arizona for the Republicans -- both considered candidates popular with the state's independent voters.
Brimming with confidence in New Hampshire after his Iowa caucus win just five days earlier, Obama drew the venom of Clinton and her husband, former President Bill Clinton, who have begun to publicly vent frustration at what they view as the media's soft treatment of Obama.
At one of his final campaign appearances, the former president, whose finish in the 1992 New Hampshire primary made him the "Comeback Kid," lashed out at Obama, calling his candidacy "the biggest fairy tale I've ever seen."
"It is wrong that Sen. Obama got to go through 15 debates trumpeting his superior judgment and how he had been against the war in every year, enumerating the years and never got asked one time -- not once, 'Well, how could you say that when you said in 2004 you didn't know how you would have voted on the resolution?'" Clinton said, suggesting that Obama had a muddled 2004 calling into question Obama's early position on the Iraq War.
"I understand he's feeling a little frustrated right now," Obama said Tuesday, noting he expects more attacks. "I don't think it will be just in the next few days," Obama said. "I think it'll be, you know, until I'm the nominee or until I quit."
Arguing her two Democratic rivals have formed "kinda a buddy system," Clinton told ABC News' Diane Sawyer on "Good Morning America" that Obama and Edwards have been given a "free ride" from the media.
"You know for both Sens. Edwards and Obama, they've been given pretty much a free ride and that's fine," Clinton said. "I don't mind having to get up there and take all the scrutiny. But at some point the free ride ends, maybe it ends now, maybe it ends in a month maybe it ends in the general election. You cannot be elected president if you do not withstand the tough questions."
But the attacks didn't appear to dent Obama's stride.
The Illinois senator got some comic relief on the campaign trail when Seinfeld co-creator and comedian Larry David accompanied his growing entourage.
When a Dartmouth student collapsed at a rally at Dartmouth College Tuesday, David cupped his hand to his mouth and called out to Obama: "Sinatra had this effect on a crowd."
"That's right, Larry," Obama said.
In Kogelo, the western Kenyan village of Barack Obama's father, the senator's distant relatives listened to the radio Tuesday for news of how Obama would do in the New Hampshire primary.
All of the Democratic candidates poured resources into the Granite State.
Clinton spent the most in the state on television advertising -- $5.4 million, to Obama's $5 million, according to TNS Media Intelligence.cmag, a firm that tracks political advertising. Reflecting a much smaller treasure chest, Edwards spent $1.7 million and New Mexico Gov. Bill Richardson, the fourth candidate in the race, spent about $500,000.
But in the end, it was Clinton who beat out her Democratic rivals, securing her position as a leading Democratic presidential candidate.
ABC News' John Donvan, Kate Snow, Sarah Amos, Raelyn Johnson, Sunlen Miller and Gary Langer contributed to this report.