Most scientists believe the Hohokam arrived in Arizona from Mexico around 300 B.C. Apparently, they arrived with a strong culture intact and had an immediate influence on the area and the people already living here. In time their influence would be felt as far west as the Colorado River, to the east, New Mexico and north to the Flagstaff area.

The 13,000 square-mile watershed above the Salt River provided a reliable water supply. During normal years, the river was probably a hundred feet wide and five to six feet deep. The banks were held in check by tall stands of willow and cottonwood trees. Digging by hand without beasts of burden (the Spanish didn’t introduce oxen, horses or mules until the 16th-century) they engineered the largest prehistoric irrigation project in North America.