Democratic nominee Hillary Clinton has opened up a commanding lead against Donald Trump in his home state of New York, thanks in part to Republicans.

According to a new Siena Research Institute poll of registered voters conducted last week and released Monday, Clinton beats Trump by 30 points — 57 percent to 27 percent — in a head-to-head matchup.

Clinton's lead is boosted by Republicans, many of whom prefer her over Trump. In a one-on-one matchup, Trump only wins 55 percent of Republicans, and 24 percent choose to back the Democratic nominee. Clinton, on the other hand, has 81 percent of Democrats when put up against just Trump. Independents side with Clinton by 10 points in the two-way race.

As of late June, the Siena poll had Trump garnering 68 percent of GOP voters.

Trump's numbers are worse when third-party candidates are included in the race. With four candidates, only 52 percent of Republicans said they planned to vote for Trump, and 20 percent chose Clinton. Another 9 percent said they would vote for Libertarian candidate Gary Johnson and the Green Party's Jill Stein got 4 percent.

And though her favorability continues to be low in the Empire State — 55 percent of voters view her favorably compared to 46 percent unfavorably — she still outdoes Trump, who is viewed favorably by only 24 percent and unfavorably by 72 percent.

The telephone poll of 717 registered New York voters was conducted Aug. 7-10 and carries a margin of error of plus or minus 4.3 percentage points.