Donald Trump keeps his one point lead over Hillary Clinton in Iowa, according to a new poll released Thursday. | Getty Poll: Clinton and Trump in dead heat in Iowa

Hillary Clinton and Donald Trump are locked in a statistical tie in Iowa, according to a new poll out Thursday.

The Manhattan billionaire leads the former secretary of state by a single point, 41 percent to 40 percent, among likely voters who responded to the Suffolk University poll.

In a four-way race that includes Libertarian Gary Johnson and the Green Party’s Jill Stein, Trump keeps his 1-point lead over Clinton, 37 percent to 36 percent, while Johnson earned 6 percent, and Stein earned 3 percent. Johnson polled much higher, 11 percent, in Southwest Iowa, one of the state’s more conservative regions, while Stein earned the support of 9 percent of likely Iowa voters between 18 and 34 years of age.

While Clinton’s post-convention bounce and the Trump campaign’s recent struggles have afforded her growing leads nationwide and in multiple swing states, Iowa has remained stubbornly close. The state has been blue in six of the past seven presidential elections, landing in the Republican column only during George W. Bush’s 2004 reelection campaign during that stretch.

It is also the state that derailed Clinton’s presidential ambitions in 2008 when she lost its Democratic Caucus to Barack Obama and nearly did so again last February when Sen. Bernie Sanders almost defeated her there. The state’s demographics are especially challenging for Clinton, who is more dependent in Iowa than she is elsewhere on less-educated white voters, a group that strongly supports Trump.

The poll also shows Republican Sen. Chuck Grassley with a 10-point lead over his Democratic challenger, Patty Judge.

The Suffolk University poll was conducted from Aug. 8-10, reaching 500 Iowa voters who said they were either very likely or somewhat likely to vote in November’s general election. The poll’s margin of error is plus or minus 4.4 percentage points.