Saco Bay is a small curved embayment of the Gulf of Maine on the Atlantic coast of Maine in the United States.
Saco Bay is approximately 16 km wide, running from the Fletcher Neck (the Biddeford Pool peninsula) and the mouth of the Saco River in York County north to the Scarborough River and Prouts Neck in Scarborough, Cumberland County, Maine, approximately 19 km southwest of Portland. The shoreline of the bay makes the largest sand beach and salt marsh system in Maine and contains the longest unbroken stretch of beach in the state.
