By contrast, according to the poll, former Sen. Rick Santorum of Pennsylvania won among voters between 40 and 64, while former Massachusetts Gov. Mitt Romney won among voters 65 or older.
Voters at the caucuses tended to be older citizens, according to the poll, with fully 60 percent of them being at least 50 years of age.
Only 25 percent of the caucus-goers were under 40, and only 15 percent were under 30.
Paul’s support in the caususes was strongest among the very youngest voters. Among caucus-goers 17 to 24, who made up 10 percent of voters, Paul took 50 percent of the vote. Santorum ran second in this age bracket, taking 21 percent, followed by Romney at 13 percent, Texas Gov. Rick Perry at 8 percent, former House Speaker Newt Gingrich at 5 percent, and Rep. Michele Bachman at 1 percent.
Among caucus-goers 25 to 29, who made up only 5 percent of voters, Paul won 45 percent, Santorum placed second with 27 percent, Romney took third with 12 percent, followed by Perry at 7 percent, and Gingrich and Bachmann at 4 percent each.
In the 30-to-39 age bracket, which made up 10 percent of caucus-goers, Paul took 34 percent, Santorum took 30 percent, Romney took 17 percent, Gingrich took 12 percent, Perry took 4 percent, and Bachmann took 2 percent.
In the 40-to-49 age bracket, which made up 14 percent of caucus-goers, Santorum won with 25 percent, according to the entrance poll. He was followed closely by Romney, who took 23 percent of this age bracket, followed by Paul who took 17 percent and Gingrich who took 16 percent.
In the 50-to-64 age bracket, which made up 34 percent of caucus goers, Santorum edged out Romney, 27 percent to 26 percent, according to the poll. Paul edged out Gingrich for third place in this bracket, 17 percent to 16 percent.
Among the 26 percent of caucus-goers who told the entrance poll they were 65 or older, Romney won 33 percent. Santorum finished second with 20 percent, followed by Gingrich at 17 percent, Perry at 13 percent and Paul at 11 percent.
The entrance poll was based on interviews with 1,787 caucus-goers.
The actual final vote tally in the Iowa caucuses was: Romney, 30,015; Santorum, 30,007; Paul, 26,219; Gingrich, 16,251; Perry, 12,604; Bachmann, 6,073; Huntsman, 745.