The unincorporated community of Blackhawk, noted for its elaborate houses and smattering of celebrities, is located in the rolling hills of Tassajara Valley east of Blackhawk. Established as a ranch in 1917 by San Francisco capitalist Ansel Easton, the ranch was used first as a summer home and later as a working ranch. The ranch gained a worldwide reputation for pure-bred Shorthorn cattle and prize Shire horses. The name Blackhawk actually came from a famous Irish race horse that the Easton family owned at one time. Walnut trees also were grown there, and for many years the ranch was known as one of Contra Costa County’s most productive. The original 1,250 acre ranch changed hands several times, growing to about 6,500 acres until it was sold in 1973 to the Blackhawk Corp, controlled by Ken Behring (eventual owner of the Seattle Seahawks of the NFL).