Mar-a-Lago () is a resort and National Historic Landmark in Palm Beach, Florida, built from 1924 to 1927 by cereal-company heiress and socialite Marjorie Merriweather Post. The 126-room, 62,500-square-foot (5,800 m²) house contains the Mar-a-Lago Club, a members-only club with guest rooms, a spa, and other hotel-style amenities. It is located in Palm Beach County on the Palm Beach barrier island, with the Atlantic Ocean to the east and Florida's Intracoastal Waterway to the west.
At the time of her death in 1973, Post bequeathed the property to the National Park Service, hoping it could be used for state visits or as a Winter White House. However, because the costs of maintaining the property exceeded the funds provided by Post, and it was difficult to secure the facility (as it is located in the flight path of Palm Beach Airport), the property was returned to the Post Foundation by an Act of Congress in 1981.
In 1985, Mar-a-Lago was purchased by Donald Trump. His wife at the time, Ivana Trump, was charged with running the property. Trump retained Mar-a-Lago through both of his divorces. His family maintains private quarters in a separate, closed-off area of the house and grounds. Trump has frequently visited there since he was elected President of the United States, referring to it as the Winter White House and his "Southern White House." It is the second largest mansion in the state of Florida and the 21st largest mansion in the United States.