Del Norte Coast Redwoods State Park is a state park of California, United States, and a component of the Redwood National and State Parks. The property is about half old-growth forest of coast redwoods and includes 8 miles (13 km) of wild Pacific coastline. The park was significantly expanded in 2002 with the 25,000-acre (10,000 ha) Mill Creek Addition. Originally established in 1925, the park is now 31,261 acres (12,651 ha). The park was designated part of the California Coast Ranges International Biosphere Reserve in 1983.