The Catskill Mountains, also known as the 'Catskills', are a smaller sub group of the larger Appalachian Mountains, located in southeastern New York. As a cultural and geographic region, 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.

The Catskills are well known in American culture, both as the setting for films and works of art, including many 19th-century Hudson River School paintings, as well as for being a favored destination for vacationers from New York City in the mid-20th century. The region has many large resorts and is a popular honeymoon venue. In addition, the Catskills have long been a haven for artists, musicians, and writers, especially in and around the towns of Phoenicia and Woodstock.

The Appalachians are among the oldest mountains on Earth, born of powerful upheavals within the terrestrial crust and sculpted by the ceaseless action of water upon the surface. The types of rock that characterize the present Appalachian ranges tell much of the story of the mountainsโ€™ long existence.

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