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
New York State Route 185 final curve to the northeast, NY 185 begins to cross Lake Champlain by way of the bridge. The route ends at the Vermont state line at the bridge's midpoint, and the roadway continues into Vermont as VT 17. The Champlain Bridge was built in 1929, connecting Crown Point in New York to Chimney Point in Vermont. A short connector highway between the bridge—which connected to VT 17 in Vermont—and NY 22 in Crown Point, named Bridge Road, was originally designated as NY 347 as part of the 1930 renumbering of state highways in New York. NY 347 became part of