The Shawangunk Ridge , also known as the Shawangunk Mountains or The Gunks, is a ridge of bedrock in Ulster County, Sullivan County and Orange County in the state of New York, extending from the northernmost point of New Jersey to the Catskill Mountains. Shawangunk Ridge is the continuation of the long, easternmost ridge of the Appalachian Mountains; the ridge is known as Kittatinny Mountain in New Jersey, and as Blue Mountain as it continues through Pennsylvania. This ridge constitutes the western border of the Great Appalachian Valley.