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Lake Ronkonkoma Watershed Management Plan


map of long island with a focus on the lake ronkonkoma area


Lake Ronkonkoma is the largest freshwater lake on Long Island. Lake Ronkonkoma was once a popular Long Island summer resort in the late 19th and early 20th centuries. Suffolk County, the Town of Brookhaven, Town of Islip, and Town of Smithtown all own parts of the lake surrounding shoreline. Working together as members of the Lake Ronkonkoma Inter-Municipal Organization and Lake Ronkonkoma Advisory Board these groups advance issues pertaining to the lake surrounding the watershed.


Lake Ronkonkoma circa 1915

circa 1915

New York State Department of Environmental Conservation

Lake Ronkonkoma is listed on NYS Department of Environmental Conservation’s 303(d) List of Impaired Waters requiring water quality development. Water quality is threatened and public bathing and recreation is impaired. Known pollutants include pathogens such as cyanobacteria and phosphorous and suspected sources include but are not limited to urban/storm runoff.

Suffolk County received $60,000 in grant funding provided by the New York State Department of State under Title 11 of the Environmental Protection Fund to create a comprehensive watershed management plan. Working with the community, the County gathered input, collected and analyze watershed data, and developed management recommendations for both restoration and protection of water quality and public access, culminating in the publication of the Lake Ronkonkoma Watershed Management Plan.


Implementation of the plan will restore the Lake to a fully functioning recreational space, improving water quality and contribute to a greater quality of life. The restoration of the Lake and surrounding watershed will contribute to economic development at the future, fully completed Ronkonkoma Hub by serving as a free cultural attraction that will enhance downtown living and help create a stronger sense of place within the community.

the shoreline of Lake Ronkonkoma

Suffolk County Government

H. Lee Dennison Bldg

100 Veterans Memorial Hwy
P.O. Box 6100
Hauppauge, NY 11788

Riverhead County Center

County Road 51
Riverhead, NY 11901