The area was first occupied by the Esselen American Indians who followed local food sources seasonally, living near the coast in winter, where they harvested rich stocks of mussels, abalone and other sea life. In the summer and fall they move inland to harvest acorns gathered from the black oak, canyon live oak and tanbark oak, primarily on upper slopes in areas outside the current camp's location.: A large boulder with a dozen or more deep mortar bowls worn into it, known as a bedrock mortar, is located in Apple Tree Camp on the southwest slope of Devil's Peak, north of the Camp Pico Blanco. The holes were hollowed out by Indians who used it to grind the acorns into flour. Other mortar rocks have also been found within the Boy Scout camp at campsites 3 and 7, and slightly upstream from campsite 12, while a fourth is found on a large rock in the river, originally above the river, between campsites 3 and 4.