 It is part of Delaware's inland bay system, along with Little Assawoman Bay and Indian River Bay.According to the Rehoboth Bay Sediment Management Plan, Rehoboth Bay is part of Delaware's Inland Bays which encompass Rehoboth Bay, Little Assawoman Bay, and Indian River Bay.Both Rehoboth Bay and Little Assawoman Bay are barbuilt
estuaries, while Indian River Bay is a drowned river valley.