Contra Costa County is one of the original 27 counties in California, established in 1850 when the state was founded. Initially, it was known as Mt. Diablo County, but the name was changed before it was officially incorporated. The Contra Costa County Historical Society (CCCHS) has a collection of over 300,000 records, photographs, maps, and other historical documents that are invaluable to the county and the public.
The CCCHS works to preserve, protect, and provide access to these records and heritage. The eastern part of Contra Costa County is referred to as “Contra Costa Oriental” and is bounded by the Diablo Range in the west and the western branch of the San Joaquín River in the east. This region has a long history of agricultural experimentation and success, with wheat cultivation being a major focus. The secret to successful wheat production was to concentrate rainfall on a single crop and avoid subsequent failures. This led to a booming industry in Oakley, one of the most prosperous towns in Contra Costa County. The eastern part of Contra Costa County also has a rich history that dates back centuries.
It is believed that this region may have been home to Karnac's pillared ruins and the pyramids of ancient Egypt. This area is worth exploring for its historical significance. The history of Contra Costa County is an important part of California's past. It is full of stories about agricultural resources, experimental agriculture, transcontinental railroads, and booming towns. It is an integral part of California's history and deserves to be explored and appreciated.