A small paleontological survey in Benton County identified numerous fossilized skeletal remains, proving prehistoricmammoths, bisons, early horses, and other animals once populated the hills. The majority of the skeletal fragments were found in canyons under fine silt and sand. They date from 7,000 to 12,000 years old, with some specimens found to be even older. The higher altitudes where the specimens were found indicate the now extinct animals survived massive flooding that followed the Ice Age.
James Gordon Kinney, an early pioneer, is credited with officially naming the Horse Heaven Hills in 1881. He first came to the region in 1857. Impressed by the knee-high grass that fed the large bands of feral horses that roamed, he remarked "the area offers excellent forage and comparative isolation... This is surely a horse heaven!"
Irrigation has recently made parts of the Horse Heaven Hills into an important agricultural region. Chateau Ste. Michelle operates the single largest wine making facility in the state of Washington in the town of Paterson.
Several intermittent streams rise in the Horse Heaven Hills, including Amon Creek.