A 1931 view of the famous Pico No. 4 oil well. A print of this photograph was donated by Standard/Chevron in the 1990s to the Santa Monica Mountains Conservancy. According to the City of Los Angeles Public Library, which has another copy of this photograph in its collection, the photo was shot March 11, 1931, and is attributed to the Los Angeles Herald-Examiner newspaper.

Fifty barrels of oil shot out of a newly-deepened California Star Oil well on September 26, 1876. Known alternately as "Pico No. 4" or "CSO No. 4," it was the first commercially successful oil well in the western United States.

This photograph of Pico No. 4 was taken in 1883. The well was tucked away in the Santa Susana Mountains formation of Pico Canyon, approximately four miles west of the present-day Lyons Avenue exit off of California Interstate 5 in the Santa Clarita Valley. It had been punched to a depth of 617 feet by a French immigrant named Charles Alexander Mentry, just 30 years old but nonetheless a veteran of the world's first commercial oil fields in Titusville, Pennsylvania.

Transient oil workers migrated to Pico Camp to harvest the bounty, and by 1880, as many as 100 families lived in what was now being called Mentryville. Not only did Pico No. 4 give birth to an industry in California; it was also the longest-running oil well in the world when it was finally capped off in September of 1990.

Further reading:

Pico Canyon / Mentryville Index

The Pico Ghost Camp by Arthur B. Perkins, 1962.

The Story of Mentryville by Leon Worden, 1996 ff.