This five-bay-façade, two-and-a-half-story Federal house stands gable end to the street, a siting not uncommon for relatively wide houses built on narrow lots in this part of town. On the exterior, the relatively simple box-like form is distinguished by its handsome principal entrance, framed by sidelights and capped with a console entablature, and a rope-molding cornice, a popular form in which quarter-round molding was drilled in a spiral pattern in imitation of twisted rope, an allusion particularly apt in a maritime community where rope played an important role commercially. Tillinghast himself, like many of his neighbors, played a role in that economy as a sail maker with his shop nearby, down the hill on South Water Street.
The Tillinghast family was the original English colonial family to settle here and had held the land on which this house stands for many years before it was built. The house next door at 401 Benefit Street was also built by a family member. The family burial ground remains nearby, adjacent to the Barker Playhouse at 400 Benefit Street; the early English settlers buried their dead in family plots like that one, but of the many active in the 17th and early 18th centuries, the Tillinghast lot is the only one extant.
— 2008 Festival of Historic Houses Guidebook