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 the border with New Jersey to the Catskills. The Shawangunk Ridge is a continuation of the long, easternmost section 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.

Rondout Creek is a 63.3-mile-long (101.9 km) tributary of the Hudson River in Ulster and Sullivan counties, New York, United States. It rises on Rocky Mountain in the eastern Catskills, flows south into Rondout Reservoir, part of New York City's water supply network, then into the valley between the Catskills and the Shawangunk Ridge, where it goes over High Falls and finally out to the Hudson at Kingston, receiving along the way the Wallkill River.