The Taconic Mountains are a physiographic section of the larger New England province and part of the Appalachian Mountains, running along the eastern border of New York State, United States and adjacent New England from northwest Connecticut to western Massachusetts, north to central western Vermont in the town of Brandon, after which they lose prominence and dwindle into scattered hills and isolated peaks which continue north toward Burlington, Vermont. To the south, they fade into the Hudson Highlands range.
In Massachusetts and Connecticut, the Taconic Mountains are often popularly grouped as part of the Berkshires; in Vermont they are similarly grouped as of the Green Mountains. However, the Taconic Mountains are geologically distinct from the Berkshires and Green Mountains.
The highest peak of the Taconic Mountains is Mount Equinox, with an elevation of 3,816 feet (1163 m), in Manchester, Vermont. "Taconic", a Native American name, was once transliterated as the Taghkanic--a name still used in parts of the western (New York) side of the range.
The western side of the Taconics rise gradually from a series of hills in eastern New York to a sharp mountain crest along the west border of the New England states; the east side of the Taconics falls off abruptly where river valleys divide it from the Berkshires and Green Mountains. The total length of the range is about 200 miles with a varying width of 5 to 20 miles.