Marine Protected Areas (MPAs) began with Executive Order 13158 in May 2000, when official MPAs were established for the first time.
The System as a whole is considered to be a national treasure of the United States, and some of the more famous national parks and monuments are sometimes referred to metaphorically as "crown jewels". At 13,200,000 acres (53,000 km²), it is over 16 percent of the entire system.
The system encompasses approximately 84.4 million acres (338,000 km²), of which more than 4.3 million acres (17,000 km²) remain in private ownership. The smallest unit in the system is Thaddeus Kosciuszko National Memorial, Pennsylvania, at 0.02 acre (80 m²).
Since its inception in 1916, the National Park Service has managed each of the United States' national parks, which have grown in number over the years to 59.
Yellowstone National Park was the first national park in the United States.
The act would allow the President to reorganize the executive branch of the United States government. Albright had suggested to President Roosevelt that the historic sites from the American Civil War should be managed by the National Park Service, rather than the War Department.