Republican front-runner Mitt Romney has won the Maine presidential caucuses, bouncing back from losses in three states earlier this week.
Mr Romney received 39% of the vote, with Texas Congressman Ron Paul coming second with 36%.
The outcome was a comeback for Mr Romney, who unexpectedly lost to former Senator Rick Santorum in Missouri, Minnesota and Colorado on Tuesday.
Rick Santorum received 18% of the vote and Newt Gingrich got 6% but neither candidate actively participated in the contest.
Mr Romney also got a boost earlier on Saturday by winning a straw poll among participants at a major conservative gathering in Washington DC, winning 38% of the vote to 31% for Mr Santorum.
The Conservative Political Action Conference (CPAC) has become an election-year must-do for candidates seeking the Republican nomination.
Conservatives in the US traditionally have strong views on issues like same-sex marriage, abortion and the role of government in people's lives.
The four candidates all pleaded their case to be the party's standard-bearer last November.
Mr Romney is often viewed with suspicion by conservatives because of his record as governor of the more liberal state of Massachusetts and claims he has changed position on those key issues.
Margaret Rogers, a conservative who travelled to the CPAC conference from her home in New Hampshire, said: "He isn't really one of us. He tries to be but he's just not."
Her husband Mike added: "The people, the Tea Party, the people at the bottom want a conservative who is going to cut back government and stop the spending before we look like Greece."
To many conservatives Mr Santorum offers everything that Mr Romney does not. He is regarded as a strong defender of the conservative cause.
He told the audience: "We should recognise that as conservatives and Tea Party folks that we are not just wings of the Republican Party, we are the Republican Party."
But in the week he picked up victories in three states he courted controversy by declaring his belief that man-made climate change was a "hoax".
While winning over conservative Republicans is important, the eventual candidate knows he will eventually have to appeal to the broader electorate, including critical moderate and independent voters.
Senior Republicans have dismissed suggestions that the gulf between conservatives and moderates in the Republican Party is too wide.
Senator James Inhofe, who has also dismissed the threat of climate change, told Sky News: "They come together because there are certain basic core things that Republicans, whether they're moderates or conservatives, agree with."
There was a noisy anti-capitalist 'occupy' demonstration outside of the hotel where the conference was taking place.
Some protesters, wearing badges representing 'the 99%', caused disruption inside when they blocked the view of television screens during a speech by Mr Romney. After some shouting and pushing, they were removed.
The next major contests in the Republican primary season come in Arizona and Michigan at the end of the month. 'Super Tuesday', when 10 states vote, takes place on March 6.