Facts & Figures

Vital Narragansett Bay Statistics

  • Length: 25 miles (40 kilometers).Smoke on the bayNarragansett Bay in the winter
  • Width: 10 miles (16 kilometers).

    Smoke on the water
  • Surface Area: 147 square miles.
  • Volume: 706 billion gallons (2.7 billion cubic meters) at mid-tide.
  • Average Depth: 26 feet (7.8 meters).
  • Deepest Point: 184 feet (56 meters) in East Passage off Castle Hill.
  • Shoreline: 256 miles (412 kilometers) including island shorelines.
  • Watershed Area: 1,853 square miles (4,081 square kilometers); 60% in Massachusetts, 40% in Rhode Island.
  • Average Salinity: The average surface salinity ranges from 24 (upper bay) to 32 (towards Ocean) parts part thousand (ppt).
  • Daily Freshwater Input, Rivers: 2.1 billion gallons.
  • Daily Freshwater Input, All Sources: 2.4 billion gallons.
  • Largest Rivers Entering Narragansett Bay: Pawtuxet, Blackstone, Taunton. Average Temperature (mid-Bay): 32F in the winter, 69F in the summer.
  • Average Flushing Time: 26 days.
  • Tidal Range: 3 to 4 feet every 12 hours; tide takes about 20 minutes to move up the Bay from Newport to Providence.
  • Prevailing Winds: From the southwest in summer; from the northwest in winter.
  • Population: Approximately 1.8 million people live in the watershed: 887,863 in Rhode Island; 949,465 in Massachusetts.
  • Tourism: More than 12 million people visit Narragansett Bay each year.

*Please note:  Be sure to access the Johnson & Wales University Harborside Campus through the main entrance on Harborside Blvd. Your GPS may suggest taking Ernest Street to JWU’s Shipyard Street entrance, but that route requires a key card for entry.  

From Route I-95 North or South, take Exit 18 (Thurbers Avenue). Head downhill on Thurbers Avenue to US Route 1A (Allens Avenue). Turn right onto Allens Ave. Continue southbound on Allens Ave. into Cranston, where Allens Ave. becomes Narragansett Blvd. Turn left onto Harborside Blvd. at the traffic light by the Shell gas station. Follow Harborside Blvd. through the Johnson & Wales Harborside Campus. At the end of Harborside Blvd., turn right onto Save The Bay Drive. Save The Bay Drive becomes a circular, one-way roadway as you approach the Bay Center. Parking is available in four guest lots after you pass the main building. Enter the building through the main entrance.