The National Park Service Organic Act says protected resources should remain “unimpaired” for the enjoyment of future generations.
Congress passed the act in 1916, creating the National Park Service and defining its central mission. The law joined two goals that can sometimes seem opposed: conserving scenery, natural and historic objects, and wildlife while also allowing public enjoyment.
“Unimpaired” is significant because it does not simply mean that parks must be closed or left entirely untouched. The NPS may provide roads, trails, visitor centers, interpretation, and other facilities, but those uses must be managed so the resources are not damaged for the future.
The wording is often confused with “untouched,” a useful everyday description but not the law’s exact term. The Organic Act’s preservation standard remains one of the most frequently quoted principles in the history of the U.S. national parks.