National Park Service (NPS)Founded in 1916, the National Park Service is a bureau of the U.S. Department of the Interior. Yellowstone National Park was was established on March 1, 1872 - the first national park (and the world's first national park). The system includes 429 areas covering more than 85 million acres in every state, the District of Columbia, American Samoa, Guam, Puerto Rico, and the Virgin Islands. These areas include national parks, monuments, battlefields, military parks, historical parks, historic sites, lakeshores, seashores, recreation areas, scenic rivers and trails, and the White House. You can find a park by state, activity or topic.