Native Americans in the Pinnacles region comprised the Chalon and Mutsun groups of the Ohlone people, who left stone artifacts in the park. These native people declined with the arrival of the Spanish in the 18th century, who brought novel diseases and changes to the natives' way of life. The establishment of a Spanish mission at Soledad hastened the area's native depopulation through disease and dispersion. Archaeological surveys have found 13 sites inhabited by Native Americans, 12 of which antedate the establishment of the missions. One site is believed to be about 2000 years old. The last Chalon had died or departed from the area by 1810. From 1810 to 1865, when the first Anglo-American settlers arrived, the Pinnacles region was a wilderness without human use or habitation.