Elfin Forest Natural Area, Protected natural area in Los Osos, California.

Elfin Forest Natural Area is a 90-acre preserve of prehistoric sand dunes rising 150 feet above southern Morro Bay, north of Los Osos-Baywood. Its Coast live oaks form a pygmy woodland: the oldest are 200 to 400 years old, standing 20 feet in sheltered spots and only 4 feet near the tallest ridge. A nearly 1-mile boardwalk loop, built in 1999, crosses the property.

The dunes are prehistoric, rising 150 feet above southern Morro Bay. Since 1988 the Los Osos/Morro Bay chapter of Small Wilderness Area Preservation acquired 90 acres, which were transferred to San Luis Obispo County Parks and California State Parks on the condition of continued stewardship by the group, now Friends of El Moro Elfin Forest. The preserve opened to the public in 1994.

Before European contact, the Chumash maintained a large settlement, now called Los Osos Back Bay, on a stabilized sand dune east of the Elfin Forest. A long Chumash midden, a deposit of shell and refuse, runs through the dwarf forest and can still be seen along the boardwalk.

A boardwalk loop of nearly 1 mile (1.6 km), built in 1999 to protect the sensitive habitats, is wheelchair accessible. Viewpoint sections along it overlook Morro Bay, the sand spit and the estuary birds. The preserve opened to the public in 1994.

A long Chumash midden lies within the dwarf forest, evidence of a settlement the Chumash called Los Osos Back Bay on a stabilized dune east of the preserve. The boardwalk loop, built in 1999, keeps visitors off the fragile pygmy oak woodland and is usable by wheelchair users.