The Redwood National and State Parks (RNSP) are located in the United States, along the Pacific Ocean coast of northern California, a combined area of . The parks protect 45% i.e. , of all remaining Coastal Redwood (Sequoia sempervirens) old-growth forests. 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, and 37 miles (60 km) of pristine coastline.

In 1850, old growth redwood forest covered more than 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 unobstructed clear-cut logging, serious efforts toward conservation began. By the 1920s work of the Save-the-Redwoods League, founded in 1918 to preserve remaining old growth redwoods, eventually 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. This degree of collaboration between the National Park Service and a state park system is unique in the nation.

The ecosystem of the RNSP preserves a number of threatened animal species such as the Brown Pelican, Tidewater Goby, Bald Eagle, 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.