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 to take some of the traffic burden. On December 28, 2009, the bridge was destroyed by a controlled demolition. A new bridge was rapidly constructed by a joint state commitment, opening on November 7, 2011. North of Ticonderoga, New York, the lake widens appreciably; ferry service is operated by the Lake Champlain Transportation Company at: While the old bridge was being demolished and the new one constructed, Lake Champlain Transportation Company operated a free, 24-hour ferry from just south of the bridge to Chimney Point in Vermont at the expense of the states of New York and Vermont at a