Presumptive Democratic presidential nominee Hillary Clinton is leading in Iowa, according to a new poll.

The survey is the first in months to measure the presidential race in Iowa since the major parties resolved their primary races. Iowa is one of about a dozen states considered pivotal to the 2016 presidential contest.

Conducted last week by Public Policy Polling, the survey said that Clinton is leading Trump, 44 percent to 41 percent. Fifteen percent are undecided.

As in national surveys, both candidates are seen more negatively by Iowans than positively, although Trump is in a worse position than Clinton. The poll said that just 33 percent of Iowans have a favorable opinion of Trump, while 64 percent see him negatively. Forty-two percent see Clinton in a favorable light, while 55 percent have an unfavorable opinion of her.

Relatively few Iowans haven't formed opinion about the two major party presidential candidates, according to the poll. Just 3 percent of Iowans responding to the survey said they weren't sure how they felt about Clinton, while just 4 percent expressed no view of Trump.

The poll was conducted June 9-10 of 630 Iowans who are registered voters. It has a margin of error of plus or minus 3.9 percentage points and was commissioned by the Constitutional Responsibility Project, a group targeting Grassley over the controversy about the vacant Supreme Court seat.