 During the 10th to 8th millennia BCE, the San Juan Basin was occupied by Paleo-Indians known as the Clovis culture () and the Folsom tradition (8,500 to 7,500).Projectile points found in the vicinity of Chaco Canyon suggest that hunters may have been active in the region as early as 10,000.By 6,000 the Picosa culture had developed from within the Paleolithic population, as environmental changes caused the eastward movement of animals and people to the Southern Plains, bringing Southwestern and northern Mexican cultures into the San Juan Basin.