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 by Carleton E. Watkins on June 26, 1877. 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.
The Story of Mentryville.