The Hoosic River, also known as the Hoosac, the Hoosick (primarily in New York) is a 70 mile (113 km) long tributary of the Hudson River, in the northeastern United States. The Hoosic River Watershed is formed from tributaries originating in the Berkshire Hills of Massachusetts, the Green Mountains of Vermont, and the Taconic Mountains. The main (South Branch) of the river begins its course at the man-made Cheshire Reservoir in Berkshire County, Massachusetts. From there, the river flows north, west, and northwest, through the towns of Cheshire and Adams, the city of North Adams, and the town of Williamstown. It then travels through Pownal in the southwest corner of Vermont, after which it enters New York. There, it flows through Hoosick Falls, where it provides hydroelectric power. It terminates at its confluence with the Hudson 14 mi (23 km) above the city of Troy in the town of Schaghticoke, Rensselaer County.