Roofer in Pleasanton, CA

Before the establishment of Pleasanton in the 1850s, an earlier settlement in the location was called Alisal. It was located on the lands of the Rancho Santa Rita near the site of an Indian ranchera, around the Francisco Solano Alviso Adobe, called El Alisal (The Sycamores), one of the earliest houses built in the valley in 1844. It is still standing and serves as the centerpiece of the Alviso Adobe Community Park. Alisal, nicknamed “The Most Desperate Town in the West”, was one of the settlements located along La Vereda del Monte that was a haunt and refuge of bandits and desperados in the era following the beginning of the California Gold Rush. Main Street shootouts were not uncommon. Banditos such as Claudio Feliz and Joaquin Murrieta would ambush prospectors on their way back from the gold rush fields and then seek refuge in Alisal. In the 1860s Procopio, Narciso Bojorques and others took refuge there.

Pleasanton is located on the lands of the Rancho Valle de San José and Rancho Santa Rita Mexican land grants. Its name came from John W. Kottinger, an Alameda County justice of the peace, who named it after his friend, Union army cavalry Major General Alfred Pleasonton. A typographical error by a recording clerk in Washington, D.C., apparently led to the current spelling.

In 1917, Pleasanton became the backdrop for the film Rebecca of Sunnybrook Farm, starring Mary Pickford. The town was once home to Phoebe Apperson Hearst, who lived in a 50-room mansion on a 2,000 acres (8.1 km²) estate, now the site of Castlewood Country Club.