Poesten Kill 

The Poesten Kill watershed includes the lands draining into the Poesten Kill and its tributaries, including the Quacken Kill, Bonesteel Creek, and Sweet Milk Creek. The Poesten Kill enters the Hudson River in Troy, and the watershed extends upstream to the Poesten Kill headwaters at Dyken Pond and to the Quacken Kill headwaters at Grafton Lakes State Park.

Much of the Rensselaer Plateau lies within the Poesten Kill watershed. The Rensselaer Plateau is New York State's fifth largest forest, and its higher elevation, cooler climate, and rocky, poorly drained soils give it a landscape and ecology more like the Adirondacks than like the surrounding lower lands. The extensive forests provide habitat for birds that nest only in the interior of large forest blocks, such as the black‐throated blue warbler, scarlet tanager, wood thrush, and broad‐winged hawk. The Plateau has been designated an Important Bird Area by the National Audubon Society.

The Rensselaer Plateau's forests hold soil and contribute to the clean water draining off the Plateau. The edge of the plateau is marked by steep escarpments, where flowing streams carved gorges. The Poesten Kill flows off the plateau at Barberville Falls, a spectacular 90‐foot waterfall in Poestenkill and one of Rensselaer County's signature natural landmarks. 

The Rensselaer Plateau contains many wetlands, including peat bogs and fens which are habitat for specially adapted plants, such as the insect‐catching pitcher plant and sundew. One of the largest peatland complexes in the Poesten Kill watershed is on the Rensselaer Plateau around Cranberry Pond. The Dyken Pond Environmental Education Center and Grafton Lakes State Park, both in Grafton, offer plenty of ways to experience the natural history and beauty of the Rensselaer Plateau.

Near the Hudson River in Troy, the Poesten Kill eroded the clay and shale to carve out the Poesten Kill Gorge and form the 175‐foot Mount Ida Falls. Alewives and other fish enter the Poesten Kill from the Hudson River each spring to spawn, although their migration upstream is soon impeded by dams.