Clinton, the junior senator from New York, said she came to New Hampshire to listen to its people but "in the process I found my own voice."

"I felt like we all spoke from our hearts and I'm so gratified you responded," Clinton said. "Now together, let's give America the kind of comeback New Hampshire has just given me."

Clinton, seen as the national front-runner until recently, lost to the Illinois senator in the Iowa Democratic caucuses and was expected to be defeated in the Granite State by Obama. But with 63 percent of the vote counted, Clinton was projected the victor by NBC with 39 percent to Obama's 36 percent. Former North Carolina Sen. John Edwards trailed with 17 percent, MSNBC reported.

"For most of this campaign we were far behind," Obama said in his concession speech. "We always knew that our climb would be steep. ... With your voices and your votes you made it clear that at this moment, in this election, there is something happening in America."

Among Republicans, Arizona Sen. John McCain was ahead of former Massachusetts Gov. Mitt Romney, 37 percent to 31 percent.