WASHINGTON — Attorney General William P. Barr has booked a ballroom in President Trump’s hotel for his annual holiday party, an event that he could spend tens of thousands of dollars on and that drew criticism from ethics experts.

Mr. Barr booked the Presidential Ballroom at the Trump International Hotel for a 200-person holiday party that he holds every year. It could cost more than $30,000, according to a Justice Department official, speaking on the condition of anonymity to discuss a nongovernment function.

His decision to hold the event at the Trump hotel comes as the Justice Department works to defend Mr. Trump against charges that he is trying to profit from the presidency. In July, a federal appeals court panel in Richmond, Va., dismissed one lawsuit saying that the president had violated the Constitution by profiting from government guests who stayed at his hotel in Washington. A similar case filed by Democrats in the House is before the United States Court of Appeals for the District of Columbia Circuit. The question at the heart of both cases could be decided by the Supreme Court.

The Washington Post first reported Mr. Barr’s holiday party plans at the Trump hotel, which is blocks from both the White House and the Justice Department.