CSO Hill
Pico Canyon

The California Star Oil Company (CSO) was formed on July 8, 1876 by San Francisco financier Demetrius G. Scofield for the purpose of harvesting newly-discovered oil in Pico Canyon, at the western edge of the Santa Clarita Valley. Within months, Pico Canyon was a river of oil, thanks to the success of Scofield's chief driller, Charles Alexander Mentry, who punched the first commercially successful oil well in the western United States in the Pico field.

This photo shows the "CSO Hill" as it looked in 1885. The derrick at lower left marks CSO No. 32. The long bridge at right was destroyed in a major earthquake that was centered in Pico Canyon in 1893. The hill on the opposite side of the canyon (unseen in this photograph) was the "PCO Hill," named for the Pacific Coast Oil Company, which succeeded California Star on September 10, 1879, when Scofield reorganized his holdings.

In 1900, Scofield merged his interests with those of John D. Rockefeller's Standard Oil Company of New Jersey, which liquidated Pacific Coast Oil. On October 4, 1906, Standard's California holdings were reorganized into the Standard Oil Company of California, with Demetrius Scofield as its first president. In January 1977, Standard Oil of California was acquired by Chevron USA. For more information read The Story of Mentryville by Leon Worden.