Southern Las Trampas Land Use Plan Amendment (LUPA)

Site Description | History | Video | Events & Hearings | Project Materials | More Info. | Photos

Las Trampas Ridge / EBRPD

Site Description

The project is located in south-central Contra Costa County, on the western periphery of the San Ramon Valley within the City of San Ramon, Town of Danville, and unincorporated areas. The 756-acre project area consists of the former Peters Ranch, Chen, Elworthy, Podva properties and the Faria open space that will be coming to the Park District.

This project identifies opportunities to open up land banked properties for public access, close gaps along the Calaveras Ridge Regional Trail, and open up additional trails and access points to the public for hiking, bicycling, and equestrian activities. What is currently open for public access is a 12-car parking lot, a half-mile trail connection to Calaveras Ridge Trail, and a segment of the Calaveras Ridge Trail.


The project area is situated within a territory that was occupied by the Bay Miwok. The Bay Miwok were comprised of tribelets with lineages named for specific locations within the area they permanently occupied. The Tatcan tribelet lived in the project area in addition to Bollinger, Sycamore, and Green Valley Creeks, the western part of Mount Diablo and most of the Las Trampas Ridge.

The favorable environment of the project area, coupled with the abundance of natural resources, allowed the Bay Miwok peoples to be successful hunter/gatherers, and allowed them to establish village sites next to streams and creeks with seasonally occupied sites also located in the foothills of Mount Diablo. For the native people of east Contra Costa County, the mountain now called Mount Diablo, as well as the surrounding landscape, was sacred. Groups from distant places, such as the Sierra Nevada, revered the mountain as a place to pray and hold ceremonies, and the mountain figures prominently in several world creation myths.

The San Ramon Valley that includes present-day Town of Danville and San Ramon was used by Mission San Jose during the Spanish period (1772 to 1821) to graze sheep and cattle when the Spanish began to colonize the region and convert the Native population to Catholicism.

After Mexico gained independence from Spain in 1821, the San Ramon Valley was broken up into two large land grants, both called Rancho San Ramon.

In 1957, Bollinger Canyon Road (named after Joshua Bollinger who was the first European to settle in Bollinger Canyon) was paved by the U.S. Army to facilitate construction of the San Francisco Defense Area Site SF-25, a Nike surface-to-air guided missile system that operated from 1955 to 1959. The site was later used by the U.S. Air Force and then the California Army National Guard as a radio relay site until 1966.

Residential development was accelerated by the completion of Interstate 680 in 1965, and a severe drought in the 1970s, which put development pressure on local ranchers and farmers as grass and water for cattle diminished. As a result, many of the Valley’s ranches established in the nineteenth century were sold and developed into large subdivisions and business parks that encroached on the Valley’s walnut and pear orchards.

Bishop Ranch Pear Label / San Ramon Valley Historical Society

The Park District acquired the properties within the project area for natural resource protection and to provide recreation opportunities. Acquisition of the Peters Ranch property came in 1983 as a condition of a residential development project, as did the Elworthy property in 2015, and the Podva property in 2018. The Park District purchased the Chen property in 2007 to ensure protection of the open space from further development. The Park District expects to acquire the Faria property in 2021.

The Southern Las Trampas Land Use Plan Amendment will formally incorporate the land banked (Peters Ranch and Chen) and newly acquired properties (Elworthy, Podva, and Faria in 2021) into Las Trampas.


Ranching on Peters Ranch in 1934 / California Pioneers of Santa Clara County

Annual round ups and brandings were an essential part of raising cattle within the project area. Footage of life on the former Peters Ranch property also depict the San Ramon Valley with walnut orchards before the transformation to residential development.

Community Events and Public Hearings

Project Materials

California Environmental Quality Act

For More Information

Please contact Kim Thai, Senior Planner, at, or at (510) 544-2320 to be added to the project mailing list.


Native oak on the Peters Ranch property in spring 2017, EBRPD

Staff collecting residual dry matter sample in summer 2019, EBRPD

Mount Diablo seen from the Elworthy property in spring 2017, EBRPD