A hotel in Boston, MA attached to the Hynes Convention Center which has hosted many Boskones (Boskones 10-16, 18, 23-24, 40-43) and all four Noreascons. It is also called the Sheraton Boston Hotel and Towers when it's feeling formal.
The Sheraton-Boston is part of the Prudential Center, the Pru, and located in the Back Bay area of Boston. It consists of two towers containing around 1200 sleeping rooms and a varied set of function rooms on the lower levels. The hotel is fairly old, having been built in the fifties, but it was massively renovated in the 70s and has continued to be modernized since.
Before the 70s renovation, one of its charming features was single rooms which were only slightly larger than a modern hotel bathroom. During the renovation, they were merged by pairs into larger rooms (which were still smallish by modern stands), each with two doors.
Fandom's relationship with the Sheraton-Boston has been somewhat rocky with Boskone having been kicked out following the Boskone from Hell in the mid-80s. Subsequently, both Noreascon and Boskone have successfully returned. It is not currently being used for a sf convention because of a combination of somewhat awkward function space layout and the high prices it is able to command due to its location.