The U.S. Grant Hotel is a historic and one of the oldest hotels in downtown San Diego, California operating under a franchise of Marriott International as part of their Luxury Collection brand. It is listed on the National Register of Historic Places. It is 11 stori…The U.S. Grant Hotel is a historic and one of the oldest hotels in downtown San Diego, California operating under a franchise of Marriott International as part of their Luxury Collection brand. It is listed on the National Register of Historic Places. It is 11 stories high and has 270 guest rooms in addition to meeting rooms and multiple ballrooms.