Check Out Mansion Trump Spent Saturday Night Partying At

Donald Trump attended a lavish Christmas costume party Saturday night at a Long Island mansion owned by a top campaign donor, billionaire Robert Mercer.

The party was held at Mercer’s 'Owl’s Nest' estate in Head of the Harbor, west of Stony Brook, NY. Mercer is Co-Managing Director of Renaissance Technologies, one of the world's biggest hedge funds.

Trump’s motorcade arrived at the mansion about 8:35 p.m. Trump, who did not wear a costume, mingled with guests at the Mercer family estate for the annual Christmas party; this year's theme was "Villains and Heroes." An invitation to the annual December party is a coveted ticket in Republican circles, never more so than this year. Several strategists who helped engineer Trump's upset win were attending, including incoming White House senior counselor Stephen Bannon and senior aide Kellyanne Conway.

Both Conway and Bannon have close ties to Rebekah Mercer, the daughter of hedge fund manager Mercer. The younger Mercer became Trump's leading and most influential donor and urged him to bring Bannon and Conway into the campaign in August.

Here are a few images of Mercer's mansion on Long Island, where the party was held.