Rhode Islanders give the special name 'salt pond' to what are usually called coastal lagoons. Coastal lagoons or salt ponds lie behind narrow barrier beaches all along the U.S. Atlantic and Gulf coasts and low- lying coasts around the world.
Salt ponds are shallow, estuarine ecosystems that vary a great deal in size, shape, and salinity.
Rhode Island's salt ponds have very irregular shapes because of their glacial origin. Ninigret Pond is the largest of nine salt ponds on the western side of Narragansett Bay.