National Park System

On August 25, 1916, President Woodrow Wilson signed the "Organic Act" creating the National Park Service, a federal bureau in the Department of the Interior responsible for maintaining national parks and monuments that were then managed by the department. The National Park System has since expanded to 430 units (often referred to as parks), more than 150 related areas, and numerous programs that assist in conserving the nation's natural and cultural heritage for the benefit of current and future generations.


The National Park Service manages 430 individual units covering more than 85 million acres in all 50 states, the District of Columbia, and US territories. While there are at least 19 naming designations, these units are commonly referred to as "parks." Multiple parks may be managed together as an administrative unit within the National Park Service. (See more information about recent changes in the National Park System and park anniversaries.)

Related Areas

Related areas are linked in importance and purpose to places managed directly by the National Park Service by preserving important segments of the nation's natural and cultural heritage. They are designated by acts of Congress or by the Secretary of the Interior (affiliated areas). The majority of related areas are not units of the National Park Service and are managed by other government agencies or non-government organizations and landowners. The National Park Service is involved in related areas by directly managing the entire or sections of a related area, or by providing technical or financial assistance.

Last updated: July 17, 2024