Harmony Headlands State Park, Coastal state park in San Luis Obispo County, United States

Harmony Headlands State Park covers 748 acres (303 ha) of undeveloped Pacific coast in San Luis Obispo County, reached from Highway 1 between Cayucos and Harmony. A 1.5-mile (2.4 km) trail crosses a marine terrace grassland toward ocean views. The land was a Storni family dairy farm until the mid 1960s.

The area became a state park in 2003 to protect California's natural coastal ecosystems for future generations. This protection preserved a significant stretch of undeveloped shoreline from intensive development.

The park lies within Rancho San Geronimo, an 1842 Mexican land grant. From 1912 the Storni family ran a dairy farm on a 750-acre parcel here until the mid-1960s, and the land was later sold to developers before conservation buyers stepped in. Volunteers now staff the unstaffed park, offering interpretation to visitors.

The park sits right off Highway 1 with parking areas and trails suited for different ability levels. Good footwear helps on routes crossing grassland and rocky ground.

Harmony Headlands is the only public access to the coast between Cayucos and Harmony, and its 1.5-mile trail crosses a marine terrace grassland. The park is unstaffed, but volunteers provide interpretation; a portable toilet stands near the small parking area.