Mike Huckabee was declared the winner of the Iowa Republican presidential caucuses Thursday night, less than an hour after voting began.

With 25 percent reporting, Huckabee had 35 percent, Mitt Romney had 24 percent and Fred Thompson had 14 percent. John McCain had 12 percent, according to the reporting.

The Iowa caucuses sites were reportedly more heavily populated than expected Thursday night as voters traveled to familiar places to throw their support to their choice of presidential candidate.

Campaign manager Chip Saltzman reported that Huckabee was delayed 30 minutes trying to access a caucus site in Waterloo. That's rural Iowa, Blackhawk County, about 90 minutes by car from Des Moines. Traffic into the caucus location was "at a standstill," Saltzman said.

The Romney campaign, however, said it considered Huckabee's campaign to be "a one-hit wonder," as the former Arkansas governor does not have the organization or money to launch a nationwide campaign.

Romney was gracious, however, when conceding Huckabee's victory.

"This is obviously a bit like a baseball game," he said. "First inning in, well it’s a 50-inning ballgame. I’m gonna keep on battling all the way and anticipate I get the nomination when it’s all said and done, but you know congratulations for the first round to Mike, and we’ll go on to New Hampshire."

First-tier candidates were hoping for break-out numbers to distinguish them in a hotly-contested race. The fate of a few second-tier contestants was hanging in the balance as their fortunes were being measured in the shadow of better-funded and organized opponents.

Entrance polling for FOX News also offered an uncertain picture on the Democratic side. As Democrats entered the caucuses, Barack Obama had 34 percent, compared to 27 percent for Hillary Clinton and John Edwards at 21 percent, though that number appeared to be moving up as the night continued.

But as 46 percent of the precincts were reported, Obama had 34 percent, and Edwards and Clinton were tied with 32 percent each. Bill Richardson had 2 percent.

Registration at one precinct at Iowa State Historical Museum was approaching 40 percent before the cut-off. That would be four times the amount the Democratic precinct chairman was expecting. Chairman Jack Porter of the 64th Democratic precinct in Des Moines told caucus-goers right before the 7 pm deadline for registration to participate that "everyone who wants to register can register," generating strong applause from those in the room.

Analysts say turnout at other locations has also been much higher than the previous election, which could bode well for Obama, who has fashioned himself the candidate for change and is attracting new voters.

Public schools, libraries, churches and city halls are many of the locations where Iowa decision-makers were headed to cast their vote to choose delegates to attend a series of conventions that will determine the state's representatives to the Democratic and Republican national conventions next summer.

The museum, for instance, is home for five of the 1,781 precincts -- three Democratic, including the 64th, and two Republican -- caucusing. People were required to have come through the door before 7 p.m. CST in order to participate so voting could begin promptly. That appeared impossible as the deadline rolled by.

Of the 3 million residents in Iowa, 2 million are registered voters, but only about 150,000 Democrats and 80,000 Republicans were expected to show at the caucus sites.

But top Obama advisers predict turnout in Democratic caucuses to exceed 200,000. If true, all the campaigns -- Obama, Clinton, Edwards -- say that would spell an Obama victory.

Once they arrived, the caucus-goers were to be assigned a location in each of the caucuses sites.

For Democrats, after arriving, voters checked off their names and were given a sticker with a numerical designation. The chairman of the precinct was to start his watch at 7 p.m. and give voters 30 minutes to spill into the corners of the room where each candidate has a designated spot for supporters.

After 30 minutes, the chairman was to count up the people at each of the spots to make sure there were enough to represent 15 percent of all the eligible caucus-goers in the precinct. If the candidate doesn't meet the 15 percent threshold, his or her supporters are given a second chance to regroup and pick another candidate or convince others to join them.

The horse-trading continues for another 30 minutes until only the viable candidates' supporters are standing in their spots. The chairman then uses a formula to determine how many delegates each candidate will win. The formula used is to multiply the number of members in a candidate's corner by the total number of delegates elected at the caucus and divide that by the total number of eligible caucus attendees.

(An example: If 150 people show up to a caucus that is to elect four or more delegates, a candidate must get at least 25 people in his or her corner to be viable. If a candidate has 25 caucus-goers in his corner, then following the formula, 25 x 4/150 = .67 percent, rounded up to one, the candidate wins one delegate).

The chairman then calls up the convention center to phone in his allocated delegates.

The Republicans have a much simpler process. It's a straw poll. Caucus-goers write the name they want and stick it in a box. The names are counted up and the delegates are apportioned by percentages.

FOX News' Bill Hemmer, Caroline Shively and Lee Ross contributed to this report.