Lake Lillinonah /ˌlɪlɪˈnoʊnə/ is a manmade lake located in Fairfield, Litchfield and New Haven counties of Western Connecticut, approximately 60 miles (97 km) northeast of New York City.

[3] The lake is bordered by six towns: Brookfield, Bridgewater, Newtown, New Milford, Roxbury, and Southbury.

[3] It was formed in 1955 by impoundment of the Housatonic River and the Shepaug River by the Shepaug Dam which was built by the Connecticut Light and Power Company.

[3] Some of the most expensive real estate in the Greater Danbury area is located on the shores of the lake, in the towns of Brookfield, Bridgewater and Newtown.

[4] Established to address environmental concerns and enforce boater safety rules, the authority collaborates with local governments to maintain the lake's ecological balance and enhance public access.