In New York state, the Potsdam is found primarily north and west of the Adirondack Mountains. Outcrop exposures of the Potsdam Sandstone occur throughout the Saint Lawrence lowlands, western Lake Champlain Valley, and northern Mohawk Valley. Ausable Chasm, near Plattsburgh, has a continuous exposure of a section more than thick. The formation reaches its maximum thickness of about in the northern Champlain lowland.