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
Champlain and St. Lawrence Railroad Champlain and St. Lawrence Railroad The Champlain and St. Lawrence Railroad (C&SL) was a historic railway in Lower Canada, the first Canadian public railway and one of the first railways built in British North America. The C&SL was financed by Montreal entrepreneur and brewery owner, John Molson. It was intended as a portage road to connect the St. Lawrence River valley with Lake Champlain, cutting time from the trip between Montreal and New York. Construction began in January, 1835 when surveyors determined the line would run from St. John on the Richelieu River to the nearest point on the St.