Wissahickon Creek is a tributary of the Schuylkill River in Montgomery and Philadelphia Counties, Pennsylvania.
Wissahickon Creek rises in Montgomery County, runs approximately 23 miles (37 km) passing through and dividing Northwest Philadelphia before emptying into the Schuylkill River at Philadelphia. Its watershed covers about 64 square miles (170 km).
The National Natural Landmarks (NNL) Program in the United States recognizes and encourages the conservation of outstanding examples of the natural history of the country. It is the only national natural areas program that identifies and recognizes the best examples of biological and geological features in both public and private ownership. The program was established on May 18, 1962, by United States Secretary of the Interior Stewart Udall.
The program aims to encourage and support voluntary preservation of sites that illustrate the geological and ecological history of the United States. It also hopes to strengthen the public's appreciation of the country's natural heritage. As of July 2024, 605 sites have been added to the National Registry of Natural Landmarks. The registry includes nationally significant geological and ecological features in 48 states, American Samoa, Guam, Puerto Rico, and the U.S. Virgin Islands.
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