Olympic National Park is a national park of the United States located in Washington, on the Olympic Peninsula. The park has four regions: the Pacific coastline, alpine areas, the west-side temperate rainforest, and the forests of the drier east side. Within the park there are three distinct ecosystems, including subalpine forest and wildflower meadow, temperate forest, and the rugged Pacific coast.

President Theodore Roosevelt originally designated the park as Mount Olympus National Monument on March 2, 1909. The monument was redesignated a national park by Congress and President Franklin D. Roosevelt on June 29, 1938. In 1976, Olympic National Park was designated by UNESCO as an International Biosphere Reserve, and in 1981 as a World Heritage Site. In 1988, Congress designated 95 percent of the park (1,370 square miles (3,500 km²)) as the Olympic Wilderness, which was renamed Daniel J. Evans Wilderness in honor of the former Washington state Governor and U.S. Senator Daniel J. Evans in 2017. During his tenure in the Senate, Evans co-sponsored the 1988 bill that created the state's wilderness areas. It is the largest wilderness area in Washington.