NEW GLOUCESTER, Maine (Reuters) - Maine's Republican presidential caucuses look like a two-man race between Mitt Romney, the party's current front-runner (who is trying to avoid a fourth straight state loss within a week), and libertarian-leaning Ron Paul.

Voting in dozens of local caucuses across the state has been going on since late January.

More than 20 caucuses are being held on Saturday under grey skies and intermittent snow showers, in something of a grand finale. Results will be released by the state Republican Party around 7:30 p.m. on Saturday EST.

The vote is a non-binding straw poll and will not assign the state's delegates to any of the candidates in the state-by-state process to choose a nominee to face Democratic U.S. President Barack Obama in the Nov. 6 general election.

Romney, a former governor of nearby Massachusetts, and Paul, a Texas congressman, made their final appeals to voters in southern Maine on Saturday. Paul, anticipating a strong result, plans a rally in Portland on Saturday evening.

Dressed in an Argyle sweater and blue jeans, Paul got a standing ovation in New Gloucester when he made a spirited seven-minute pitch focused on personal freedoms.

If I had to narrow it down to one word, I would narrow it down to 'liberty, said the 76-year-old former obstetrician. He then touched on property rights, taxation, bringing the troops home and returning to a gold standard for the U.S. dollar.

Property is really the essence of freedom. It's our life and our liberty, and we have to be able to keep our property, Paul said.

Voter Helen Tutwiler, 51, a housecleaner from Litchfield, praised Paul as a man of integrity who has maintained his positions for decades.

Earlier, at a large caucus site in Sanford, voters packed a high school gymnasium to hear Romney deliver a boiled-down version of his usual stump speech. He called Obama a failed president and added that he was the one person in this race that can actually beat the president.

I know what it will take to make America the best place in the world for job creation, Romney said.

Maine's population ranks 41st among the 50 U.S. states, but the contest is key for Romney after he lost to former U.S. Senator Rick Santorum in Missouri, Minnesota and Colorado this week. A win could help right the Romney ship, while a loss would be another sign that Republican voters have reservations about his conservative bona fides.

Public Policy Polling on Saturday showed Santorum, recently written off by many pundits, racing to a 15-point lead in a national poll of Republicans -- 38 percent to Romney's 23 percent -- on the back of his trifecta of wins on Tuesday.

Santorum and the fourth Republican in the field, former U.S. House Speaker Newt Gingrich, have not campaigned in Maine and have limited field operations there.

By contrast, Paul held several well-attended events in Maine in late January. A rally in Freeport on a frigid day attracted an estimated 1,000 Paul loyalists and curious shoppers at the outdoor clothing and supplies store L.L. Bean -- no small feat in a state where total votes cast in the 2008 Republican caucuses was 5,491.

Romney, endorsed months ago by many local lawmakers, made his first 2012 visit to Maine on Friday, at a packed town-hall meeting in Portland.

OCEANFRONT PALACES TO POTATO FARMS

Maine encompasses everything from oceanfront estates, such as one owned by former President George H. W. Bush in Kennebunkport, to remote potato farms near the state's northern border with Canada. Obama won the state by 18 points in the 2008 election. Maine has not voted Republican in a presidential election since 1988.

Portland, the state's largest city, is only two hours from Boston, and within Republican ranks it is regarded as natural territory for Romney, who easily won the primary in neighboring New Hampshire a month ago.

But north and away from the coast, Maine's vast, sparsely populated wilderness areas are seen as Paul strongholds -- areas where many residents have a frontier spirit and are wary of excessive government involvement in their lives.

I want to cut $1 trillion out of federal spending, Paul said in New Gloucester, to applause.

Many of Maine's rural areas are struggling economically. Romney, a multimillionaire former venture capitalist, has not fared well with lower-income voters in most states so far.

We have an extreme stratification of wealth in this country, said Richard Acheson, 43, a mechanical designer from Waterboro who backed Paul. I have no interest in Romney at all.

The caucuses have been marked by large, enthusiastic crowds, a change from other states that voted in the Republican contest so far, where turnout has often been below 2008 levels.

John Grooms, state grass-roots director for Gingrich's campaign in Maine, said turnout had been strong in many locations. I went to a caucus in Madison that had never had more than five people -- and they had 35, said Grooms.

A show of hands in Sanford suggested that more than half of those in attendance were caucusing for the first time.

(Editing by Mohammad Zargham and Jackie Frank)