On the Democratic side of the race, it remains Bernie Sanders' primary to lose, with the Vermont senator holding a 26-point lead over Hillary Clinton.
The field of candidates vying for a second place finish behind him is finally beginning to separate, according to the survey.
Trump holds 31%, down two points from the February 3-6 release, but within the poll's margin of sampling error.
Behind him, Florida Sen. Marco Rubio earned 17% support -- within the margin of sampling error of Texas Sen. Ted Cruz at 14%, but significantly ahead of the fourth and fifth place candidates in the poll, Ohio Gov. John Kasich at 10% and former Florida Gov. Jeb Bush at 7%.
Behind Bush, Carly Fiorina stands at 5%, New Jersey Gov. Chris Christie at 4% and retired neurosurgeon Ben Carson at 3%.
Aside from Trump, none of the Republican candidates moved more than 1 point in either direction compared with the previous CNN/WMUR tracking poll.
About three-quarters of the interviews conducted for this poll were completed before the Republican candidates debated Saturday night, their final such match-up before Tuesday's election.
Although the post-debate sample size is too small to produce a separate estimate of the vote, interviews conducted Sunday and Monday found no drop in support for Rubio, and actually showed a slimmer margin between Trump and Rubio.
There has been little movement in the last two days in the other metrics tested in the survey, with about two-thirds still saying they expect to see Trump win on Tuesday (64%), and about a third saying they would never vote for Trump (32%).
Over the full course of the tracking poll, there have been some shifts on the "never support" question, however, with the share saying they would not vote for Bush climbing from 7% in the first wave of data to 13% now. And the share saying they would never back Trump dipping from 37% in the first wave to 32% now. The rest of the field is within 1 or 2 points of where they started on that measure.
In the Democratic race, Sanders tops Clinton 61% to 35%, an uptick for Sanders since the last update to the tracking poll, while Clinton holds steady. Just 15% of those who say they are likely to participate in the Democratic primary say they're still undecided about whom to support, 64% say their choice is locked in.
And now, fully 60% of likely Democratic primary voters say that either Sanders or Clinton would be OK, up from 52% at the start of the tracking poll.
Still, most expect Sanders to win on Tuesday, 65% say they think he will win compared with 20% who say they think Clinton will win. That's a shift in Sanders' favor since the start of the poll, when the split was 61% Sanders to 25% Clinton.
Voters in New Hampshire who are registered as undeclared, or without any party affiliation, can choose whether to participate in the Democratic or Republican primary.
The poll indicates that undeclared voters who do want to participate in Tuesday's elections are about evenly split on which party's contest they'd rather participate in, with 47% choosing the Democrats, 46% the Republicans and 7% still not sure.
The CNN/WMUR poll was conducted by the University of New Hampshire Survey Center by telephone from February 4-8. The poll includes interviews with a random sample of 887 adult residents of New Hampshire, including 362 who plan to vote in the Republican presidential primary and 363 who say they plan to participate in the Democratic primary. For results among the sample of likely Republican primary voters, the margin of sampling error is plus or minus 5.2 percentage points, it is 5.1 points for Democrats.