In Las Vegas, three guys have a bachelor party in which hotel in the 2009 movie "The Hangover"?

In the film "The Hangover" two days before his wedding, Doug (Justin Bartha) and three friends (Bradley Cooper, Ed Helms, and Zach Galifianakis) drive to Las Vegas for a wild and hopefully memorable bachelor party at Caesars Palace, a luxury hotel and casino in Paradise, Nevada.

When the three groomsmen wake up the next morning, they can't, in fact, remember a thing. Additionally, they can't find Doug. With little time to spare, the three hazy guys try to retrace their steps and find Doug so they can leave Caesars Palace and get Doug back to Los Angeles, CA in time to get married.

"The Hangover" is an American comedy film that was directed by Todd Phillips and co-produced by Phillips and Daniel Goldberg. The screenplay was written by Jon Lucas and Scott Moore. It is the first installment in "The Hangover" trilogy. It was a critical and commercial success. Its positive reception from viewers and the press yielded many good reviews, high viewership, and several accolades from relevant institutions and organizations. The film's great commercial success is noted by its very high amount of sales. It grossed $469.3 million dollars on a production budget of $35 million.

This film was 10th-highest-grossing film of 2009 in the world, the 9th-highest-grossing film of 2009 in the US and the highest-grossing R-rated comedy ever in the United States. Out of all R-rated films, it is the 6th-highest-grossing ever in the US.