North Castle, New York in the context of "Armonk, New York"

The Kensico Reservoir is a reservoir in the New York City water supply system. Spanning the towns of North Castle and Mount Pleasant, New York, it was formed by the Kensico Dam in 1885, which impounded waters from the Bronx and Byram rivers.

In addition to being a catchment for its own drainage basin in Westchester County, the reservoir serves as a mixing basin for and stores waters from both the Catskill Aqueduct and Delaware Aqueduct, as well as the drainages of the West Branch Reservoir and Boyds Corner Reservoir (that lie within the Croton River watershed), which get mixed at West Branch with those of the Delaware Aqueduct before the combined flow is carried to Kensico.