Nye Mountain is a mountain located in Essex County, New York, named after William B. Nye (c.1815–1893), an Adirondack mountain guide. Nye Mountain is part of the Street Range of the Adirondack Mountains; it is flanked to the southwest by Street Mountain. Nye Mountain stands within the watershed of the West Branch of the Ausable River, which drains into Lake Champlain, thence into Canada's Richelieu River, the Saint Lawrence River, and into the Gulf of Saint Lawrence. The west side of Nye Mtn. drains into the headwaters of the Chubb River, thence into the West Branch. The north end of Nye Mtn. drains into the Chubb River. The east side of Nye Mtn. drains into the northern Indian Pass Brook, thence into the Ausable's West Branch. Nye Mountain is within New York's Adirondack Park.