Cayucos is located on the coast in San Luis Obispo County, California along California State Route 1 between Cambria to the north and Morro Bay to the south. The population was 2,592 at the 2010 census, down from 2,943 at the 2000 census.

Prehistorically the local area was inhabited by the Chumash people, who settled the coastal San Luis Obispo area approximately 11,000 to 10,000 BC, including a large village to the south of Cayucos at Morro Creek.

The first European land exploration of Alta California, the Spanish Portol' expedition, camped in the vicinity of today's Cayucos on September 9, 1769. Coming from the previous campsite near Morro Bay, Franciscan missionary and expedition member Juan Crespi noted in his diary that "In the four hours that we traveled, making at the most three leagues, we encountered eight arroyos by which the water from the mountains runs to the sea, along whose edge we traveled.