The Southern Pomo and Southern Wappo peoples inhabited these lands in prehistoric times. No full-scale villages have been discovered within the park boundaries. This site was valuable to the Native American tribes as a source of obsidian, which they used to make scrapers, knives, arrowheads, and spearheads. Archaeological evidence suggests they used the area as a quarry at least as far back as 3000 years. Human use and settlement of this area changed markedly in the late 18th century when the Spanish came to this region. Cattle ranching and farming gradually replaced the prehistoric tribal hunting and gathering.