The Redwood National and State Parks (RNSP) are old-growth temperate rainforests located in the United States, along the coast of northern California. Comprising Redwood National Park (established 1968) and California's Del Norte Coast, Jedediah Smith, and Prairie Creek Redwoods State Parks (dating from the 1920s), the combined RNSP contain 133,000 acres (540 km²). Located entirely within Del Norte and Humboldt Counties, the four parks, together, protect 45% of all remaining coast redwood (Sequoia sempervirens) old-growth forests, totaling at least 38,982 acres (157.75 km²). These trees are the tallest and one of the most massive tree species on Earth. In addition to the redwood forests, the parks preserve other indigenous flora, fauna, grassland prairie, cultural resources, portions of rivers and other streams, and 37 miles (60 km) of pristine coastline.
In 1850, old-growth redwood forest covered more than 2,000,000 acres (8,100 km²) of the California coast. The northern portion of that area, originally inhabited by Native Americans, attracted many lumbermen and others turned gold miners when a minor gold rush brought them to the region. Failing in efforts to strike it rich in gold, these men turned toward harvesting the giant trees for booming development in San Francisco and other places on the West Coast. After many decades of unrestricted clear-cut logging, serious efforts toward conservation began. By the 1920s the work of the Save-the-Redwoods League, founded in 1918 to preserve remaining old-growth redwoods, resulted in the establishment of Prairie Creek, Del Norte Coast, and Jedediah Smith Redwoods State Parks among others. Redwood National Park was created in 1968, by which time nearly 90% of the original redwood trees had been logged. The National Park Service (NPS) and the California Department of Parks and Recreation (CDPR) administratively combined Redwood National Park with the three abutting Redwood State Parks in 1994 for the purpose of cooperative forest management and stabilization of forests and watersheds as a single unit.
The ecosystem of the RNSP preserves a number of threatened animal species such as the tidewater goby, Chinook salmon, northern spotted owl, and Steller's sea lion. In recognition of the rare ecosystem and cultural history found in the parks, the United Nations designated them a World Heritage Site on September 5, 1980 and an International Biosphere Reserve on June 30, 1983.