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 Mountains McCullough Range of Nevada lies adjacent to the north. New York Mountains The New York Mountains are a small mountain range found in northeastern San Bernardino County in California, USA. The range's northeastern area lies in southeastern Nevada. The range lies just south of the small community of Ivanpah, and north of the Lanfair Valley. The mountains are part of the mountain ranges, cones, mountains, and landforms in the Mojave National Preserve. The mountains reach an elevation of , and run in a mostly southwest-northeasterly direction between the Providence Mountains and the McCullough Range approximately five miles into Nevada and