San Bernardino County history: Trona – Welcome to San Bernardino County

A view of the Trona Pinnacles in the desert. — *Trona Pinnacles, a major landmark in Trona.*

The community of Trona was established as a result of Searles Lake, which is known to contain a variety of minerals that attracted people to the area to mine and manufacture its resources.

In 1862, John W. Searles discovered borax on the dry barren surface of this lake while prospecting for gold and silver in the Slate Range. At first, Searles did not recognize the value of borax. It took him almost a decade and an encounter with Francis Marion Smith, “The Borax King,” before realizing the significance of what he discovered.

In 1873, Searles claimed 640 acres of the lake and formed the San Bernardino Borax Mining Company. In 1897, the San Bernardino Borax Mining Company was sold to the Pacific Borax Company, which was owned by Smith.

Trona was officially established in 1913 as a self-contained company town wholly operated by the mining company to house employees. The mining company built a library, grocery store, a school, basic housing and minimal recreation facilities. Employees of the mining company were paid in scrip, which is a temporary certificate that entitles the holder to receive a formal certificate and dividends.

In addition to borax, Searles Lake also contained 98 other chemical elements, which were used in the manufacture of fertilizer, baking soda, newsprint, brown paper, enamel, pottery glaze, cotton and more. This made the area even more attractive to miners, which led to the construction of the Trona Railway between 1913-14 to provide the town with a rail connection to the Southern Pacific line at Searles. During World War I, Trona was the only reliable American source of potash, an important element used in the production of gunpowder.

A unique feature of the community includes the Trona Pinnacles, which are considered one of the most unusual geological wonders in the California Desert. The tufa pinnacles, made of calcium carbonate, rise from the bed of the Searles Dry Lake basin. These tufa spires, some as high as 140 feet, were formed underwater 10,000 to 100,000 years ago.

A number of Hollywood films have been shot around the Trona Pinnacles, including Star Trek V: The Final Frontier and Planet of the Apes. The Trona Pinnacles were designated by the Department of the Interior as a National Natural Landmark in 1968. Today, Trona is an unincorporated community in San Bernardino County that is home to a small population.

The information in this historical feature was originally part of a video series produced by the Assessor-Recorder-County Clerk’s office.

Additional County Update News – March 27, 2025