The Lanphere Dunes are located between the Pacific Ocean and the Mad River Slough that flows through the Arcata Bottoms at the head of Humboldt Bay, about 59 miles (95 km) south of Crescent City and 8 miles (13 km) north of Eureka, California. The Lanphere Dunes are the largest remaining stand of pristine coastal dunes in the Pacific Northwest.

Coastal dunes form where sand is deposited along the coast and onshore winds transport the sand up the beach face. The Lanphere Dunes are formed from the accumulation of sediments from the Mad River. These dunes are part of a more expansive Humboldt Bay dune system that occurs along 34 miles (55 km) of the northern California coast. The dune complex consists of the beach, foredune, herbaceous and woody swales, coniferous and riparian forest, freshwater swamp, freshwater marsh, brackish marsh, salt marsh, and intertidal mudflats.

The area was historically occupied by the Wiyot people prior to European settlement. In the 1930s, William and Hortense Lanphere lived here and for 40 years they maintained the dunes in a relatively pristine state. In 1975, a movement for permanent protection was made by the Lanphere’s and faculty from Humboldt State University who used the area for botany classes. The dunes are now part of the Humboldt Bay National Wildlife Refuge. Site management focuses on the prevention and eradication of invasive plants and the restoration of dune and estuarine processes. Read more here and here. Explore more of Lanphere Dunes here: