Mount Hope Bay is a tidal estuary located at the mouth of the Taunton River on the Massachusetts and Rhode Island border. It is an arm of Narragansett Bay. The bay is named after Mount Hope, a small hill located on its western shore in what is now Bristol, Rhode Island. It flows into the East Passage of Narragansett Bay and also the Sakonnet River. Mount Hope Bay has played an important role to the history of the area, from pre-colonial times to the present.