Washington County, New York is part of the Great Appalachian Valley (also known simply as the 'Great Valley') which is a long narrow valley strip often between tall mountain ranges. The county transitions from the Taconic Mountains to the Adirondack Mountains, and from the Lake Champlain Valley to Hudson River Valley. Much of the county is part of the slate valley of the Upper Taconic Mountains (Taghkanic, meaning 'in the trees'). The eastern boundary of Washington County is the New York–Vermont border, part of which is Lake Champlain. This is also the border with New England proper. The northern end of the county is
Lake Champlain Seaway Lake Champlain Seaway The Lake Champlain Seaway was a canal project proposed in the late 19th century and considered as late as the 1960s to connect New York State's Hudson River and Quebec's St. Lawrence River with a deep-water canal. The objective was to allow easy ship traffic from New York City to Montreal through Lake Champlain, lowering transportation costs between the two cities. Though supported by business groups in New York and Quebec, it proved economically unfeasible. Prohibitive costs (estimated at $100 million in 1900), opposition from railroads, and the diminishing utility of canal transportation prevented the project from