Indian River Bay is a body of water in Sussex County, Delaware. It is part of Delaware's inland bay system, along with Little Assawoman Bay and Rehoboth Bay. Fed by the Indian River at its western end, the bay is connected to the Atlantic Ocean to the east via the Indian River Inlet. A natural waterway that shifted up and down a two-mile (3.2 km) stretch of the coast until 1928, the inlet was kept in its current location by dredging between 1928 and 1937, and in 1938 was fixed in place by the construction of jetties.[1] The Charles W. Cullen Bridge, commonly known as the Indian River Inlet Bridge, spans the inlet.
Indian River Bay is unique among Delaware's inland bays in that it is a drowned river valley, whereas Delaware's other bays are estuaries built on sand bars.[2]