Long Island Sound Facts, Figures & Maps

Area of LIS: 1320 square miles
Drainage Basin or Watershed:16,820 square miles
Average Depth: 63 feet (60-120 feet)
Volume: 18 trillion gallons
Coastline: 600 miles
Salinity Ranges: 23 parts per thousand in the western end to 35 parts per thousand at the eastern end
Source of Fresh Water: 90% of the freshwater comes from three major Connecticut Rivers - the Thames, Housatonic, and Connecticut
Temperature: 32°F in winter and 73°F in summer
Tides: two high and two low each day with the greatest tides in the west
Population Living within 50 miles: 20 million people
Estimated Value to the Local Economy: $5.5 billion per year
Fish Populations: more than 120 species of finfish, including 21 tropical species that stray here seasonally; at least 50 species spawn in the Sound

Long Island Sound - From New York City to the Rhode Island Border

Long Island Sound Drainage Basins