Winooski River

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The Winooski River (also known as the Onion River) is a tributary of Lake Champlain, approximately 90 miles (145 km) long, in the northern half of Vermont. Although not Vermont's longest river, it is one of the state's most significant, forming a major valley way from Lake Champlain through the Green Mountains towards (although not connecting in drainage to) the Connecticut River valley.

The river drains an area of the northern Green Mountains between Vermont's capital of Montpelier and its largest city, Burlington. It rises in the town of Cabot^[1] in Washington County, and then flows southwest to Montpelier, passing through the city along the south side of downtown and the Vermont State House. From Montpelier it flows northwest into Chittenden County through Richmond, passing north of the city of Burlington. It enters the eastern side of Lake Champlain approximately 5 miles (8 km) northwest of downtown Burlington. The city of Winooski sits along the river approximately 8 miles (13 km) upstream from its mouth, on the northeastern edge of Burlington. The river was historically used for the transportation of timber in the logging heyday of Vermont during the 19th century. The valley of the river downstream from Montpelier is where both U.S. Highway 2 and Interstate 89 run between Montpelier and Burlington.

The river is one of several antecedent rivers in Vermont which predate the rise of the ancient Green Mountains, and have cut through these mountains as they rose and eroded.