Wyassup Lake is a 99-acre lake that is located in North Stonington, CT. The western side of the lake is bordered by the Pachaug State Forest. There is some residential development around the lake and a road around almost the entire lake. Public boat access is permitted and there is a DEEP boat launch on the southwestern shore. There are four islands in the middle-east portion of the lake. It is particularly rocky and shallow around the two smaller adjacent islands.

The CAES IAPP 2013 survey of Wyassup Lake found 18 species of aquatic plants. One species is invasive, variable watermilfoil (Myriophyllum heterophyllum). It was found growing mostly in the middle of coves around the lake. The most commonly found plant in the lake was a native called southern naiad (Najas guadalupensis). This plant was found growing everywhere in the lake where the depth was 1.2 to 2.5 meters. Southern naiad was present on 34 of the 100 transect points. It grew in dense mats across the bottom of the lake bed, never reaching the surface. Native plants dominated the shoreline as well, including: spikerush (Eleocharis species), waterwort (Elatine species), and primrose willow (Ludwigia species). These plants were found growing along most of the shoreline, including the island shoreline. There were sporadic spots where they would not grow, commonly where it was very rocky along the shore. The floating leaf plants white water lily (Nymphaea odorata) and yellow water lily (Nuphar variegata) were found mostly in the coves. Three bladderwort species were found growing in low abundance in various places around the lake: humped bladderwort (Utricularia gibba), common bladderwort (Utricularia macrorhiza), and purple bladderwort (Utricularia purpurea).