Photos of the Long Island Sound

Research & Monitoring


The Long Island Sound Study has launched a new version of the Environmental Indicators section. The data below may be out of date. Please visit and bookmark the new section here to see the most recent data.

Status and Trends: LISS Environmental Indicators

Watershed Population

Map shows population density of coastal NY and CT in the Sound's watershed

US Census, U Virginia Library Historical Census Browser, and NYS Data Center

US Census, U Virginia Library Historical Census Browser, and NYS Data Center

Long Island Sound Watershed Population By State
1800 251,030 41200 136,920 49,550 79,600 9,170
1850 370,800 187,200 232,870 75,920 123,100 10,770
1900 908,400 772,400 544,800 87,060 110,600 18,890
1950 2,007,300 2,833,180 914,410 110,800 117,000 39,190
1970 3,032,220 3,603,610 1,088,220 126,060 123,040 64,160
1980 3,107,560 3,240,140 1,092,670 145,890 142,800 70,240
2000 3,405,570 3,631,250 1,170,210 166,800 165,400 87,060
2010 3,574,097 3,723,619 1,203,754 176,664 167,021 88,939
Total Long Island Sound Watershed Population
1800 567,470
1850 1,000,660
1900 2,442,150
1950 6,021,880
1970 8,037,310
1980 7,799,300
2000 8,626,290
2010 8,934,094


The watershed is all of the land area that drains into Long Island Sound itself or bodies of water that connect to the Sound.  The watershed of Long Island Sound includes land from six states and extends north up to the border with Canada.The total area of  the LIS watershed in Connecticut is 3,296,015 acres, which includes nearly the entire state. The total area of the LIS watershed in New York is 306,052 acres, and is situated primarily along the coast in Long Island, Queens, the Bronx, and Westchester.


This indicator provides population information for the total watershed plus state-level data for the parts of each state within the watershed.


About 8.93 million people live in the watershed, according to the 2010 US Census, an increase of 3.5 percent from 2000. The increase is slightly higher than the 3.2 percent growth for the entire Northeast.  From 2000 to 2010, regional growth was much faster for the South and West (14.3 and 13.8 percent, respectively) than for the Midwest (3.9 percent) and Northeast (3.2 percent). About half of the watershed population lives near the coast in New York and Connecticut, according to an analysis done for a public perception survey of Long Island Sound in 2006.


Compiled by M.A. Parker, CTDEEP, from population data estimates maintained by the US Census Bureauthe University of Virginia Library with the cooperation and consent of the Inter-University Consortium for Political and Social Research, and New York census 2000 town/city data from the Empire State Development – DataCenter.

Subscribe to receive our e-newsletter, Sound Bytes by providing your email address. Interested in a free copy of our print newsletter, Sound Update? Then also provide your home/company/school address.