Chincoteague Bay (, , or ) is a lagoon between the Atlantic barrier islands of Assateague and Chincoteague and the mainland of Worcester County, Maryland and northern Accomack County, Virginia. At the bay's northern end, where it narrows between Assateague and Sinepuxent Neck, it becomes Sinepuxent Bay; Chincoteague Bay's southern end drains into the Atlantic Ocean via Queen Sound and Chincoteague Inlet.