Lake Pleasant Regional Park, within the area controlled by the Northeastern Yavapai during the historic period, was inhabited by Hohokam peoples during the prehistoric era. Five archeological sites were located during an archeological study of the Lake Pleasant area. Included in these five archeological sites were a defensive site, a stone workshop, a farmhouse, and two small villages. Undoubtedly many more sites were once present along the Agua Fria but have gone under the waters of Lake Pleasant. The five sites located during the study were occupied during the period A.D. 700 to 1450.

In the park area, high bluffs rise directly from the bed of the river, greatly restricting the amount of area available for prehistoric habitation and agriculture. Despite this restriction, the area was apparently fairly heavily populated during prehistoric times, as sites were located on almost every flat terrace close to the river.

The Lake Pleasant Regional Park area, while historically part of the mining and range industries of Central Arizona, had no significant influence upon either. Prospectors met only with frustration. The few mines that did exist in the Lake Pleasant area were short-term projects. There was no lack of prospectors who roamed the area in hopes of finding their bonanzas. Mollie Sawyer Monroe and Jacob Snively were among the more colorful.

Mollie Monroe, an eccentric female prospector during the 1860's and early 1870's, was a co-discoverer, along with her common-law husband George Monroe and others, of Castle Hot Springs. In 1877 Mollie was sent to Stockton, California, where Arizona's mental patients were kept, after being declared insane. She died in 1902 at the State Hospital in Phoenix.

Jacob Snively, a man of unbounded energy as a prospector in California and Arizona and long notorious for his leading part in the Texas Revolution, prospected the area about the same time as Mollie Monroe. Snively was killed by Big Rump (Wa-poo-i-ta), an Apache chieftain, in 1871 near the White Picacho, a prominent landmark about 18 miles northwest of the Park.

Evidence of extensive interest in mineral possibilities is visible in numerous prospect holes in the area, but a search of mining claims and claimants at the Maricopa County Recorder's office reveals only a few mining locations filed in the Park boundaries.