The West Kill, an 11-mile-long (18 km) tributary of Schoharie Creek, flows through the town of Lexington, New York, United States, from its source on Hunter Mountain, the second-highest peak of the Catskill Mountains. Ultimately its waters reach the Hudson River via the Mohawk. Since it drains into the Schoharie upstream of Schoharie Reservoir, it is part of the New York City water supply system. It lends its name to both a mountain to its south and a small town midway along its length.