Narragansett Bay Watershed map topography and watershed basins

Narragansett Bay is an estuary in New England, and the heart of the Narragansett Bay watershed. An estuary is a body of water where rivers meet the sea.

By definition, a watershed is the land area that drains into rivers, streams, lakes or estuaries. Some 40% of the Narragansett Bay watershed is in Rhode Island, but over 60% of the watershed is actually in Massachusetts.

Bay and Watershed Facts


Narragansett Bay

  • In 1987, the United States Congress named Narragansett Bay an “Estuary of National Significance”
  • Narragansett Bay is one of New England’s largest estuaries, it includes 196 square miles of estuarine waters
  • The Bay’s coastline is more than 560 miles long – farther than a round trip car ride between Boston and New York
  • There are 37 licensed marine beaches in the Bay
  • Narragansett Bay has 3,321 acres of salt marsh, and 513 acres of seagrass
  • Climate change is affecting air and water temperatures, precipitation, sea level, and fish in the Narragansett Bay


Narragansett Bay Watershed

  • The Narragansett Bay Watershed lies 40% in Rhode Island and 60% in Massachusetts
    • The Watershed is home to 1.95 million people (as of 2010)
  • The Narragansett Bay watershed includes 1,091,112 acres of land (1,705 square miles) of which 35% is urban land (378,661 acres) and 39% is forested land (424,612 acres)
  • Major cities within the watershed include: Worcester, MA, Taunton, MA, Fall River, MA, Providence, RI, Newport, RI
  • There are 37 Wastewater Treatment Facilities that drain into the Bay
  • There are 3,578 miles of streams and rivers that carry water into the Bay
  • The Narragansett Bay watershed includes 4 river basins:
    • Taunton River Basin 338,871 acres (529 square miles)
    • Blackstone River Basin 303,734 acres (475 square miles)
    • Coastal Narragansett Basin 300,124 acres (469 square miles)
    • Pawtuxet River Basin 148,404 acres (232 square miles)


Little Narragansett Bay Watershed

  • Includes 202,920.80 acres (317.10 square miles)


Coastal Ponds Watershed

  • Includes 35,922.80 acres (56.10 square miles)