Doubletop Mountain is a Catskill peak in Ulster County, New York, within Catskill State Park. It rises near Graham Mountain, Big Indian Mountain, and the Beaver Kill Range, placing it among prominent surrounding highlands. The mountain is significant as part of the Delaware River watershed: its slopes give rise to headwater streams including Dry Brook, Beaver Kill, High Falls Brook, and Pigeon Brook. Water from these streams eventually flows into the East Branch of the Delaware River, the West Branch of the Neversink River, and onward to Delaware Bay, linking the mountain directly to a broader regional drainage system.