The Catskill Mountains, also known as the Catskills, are part of the larger Appalachian Mountains. They are in southeastern New York. The Catskills are generally defined as those areas close to or within the borders of the Catskill Park, a 700,000-acre (2,800 km2) forest preserve forever protected from many forms of development under New York state law.
- "REGIONAL TOPOGRAPHY". Catskills GIS Atlas. Catskill Center. Archived from the original on 2009-10-29. Retrieved 2009-10-12.
- "Physiographic divisions of the conterminous U. S". U.S. Geological Survey. Retrieved 2007-12-06.