The South Cape Mendocino State Marine Reserve is an offshore marine protected area located off Cape Mendocino and the coastal town of Petrolia about 30 miles (48 km) south of Eureka.

The area is one of the most undeveloped sections of the California coast, and its waters are homes to important bird and mammal species.

[1] In June 2012, the California Fish and Game Commission voted unanimously 3-to-0 to designate waters in South Cape Mendocino State Marine Reserve, along with critical ocean habits in northern California, as Marine Protected Areas.

[5] The South Cape Mendocino area and its rock cliffs and pebble beaches draws windsurfers, tidepooling and wildlife viewing opportunities.

Cyclists know the cape as "The Wall" – a popular feature of the "Tour of the Unknown Coast" because of its tough 18-percent grade climb.