Pochuck Mountain is a ridge in the New York-New Jersey Highlands region of the Appalachian Mountains. Pochuck Mountain's summit and most of its peaks lie within Vernon Township, Sussex County, New Jersey, although the south-western portion of the ridge lies within Hardyston Township, and the north-eastern tip of the ridge extends over the New York state line into Orange County. The ridge marks the eastern edge of the Great Appalachian Valley, and it divides the watersheds of the Wallkill River and its tributary Pochuck Creek.