Camp Rubidoux is listed in the History of the Western Defense Command as located in the Riverside, CA area. Numerous local newspaper articles from the World War II era describe California State Guard activities taking place at Camp Rubidoux. The State Guard was formed after the California National Guard was mobilized into federal service. The State Guard was composed entirely of volunteers and their chief duties involved guarding war plants. They were also available to defend their local community in the event of sabotage or attack. No information was located indicating use of the property by the U.S. Army or National Guard units mustered into federal service.
The records of the California State Guard
indicate that this post was garrisoned by the 5th Regiment and
that the regiment operated a hospital for its assigned guardsmen. After 1943, it was garrisoned by the Headquarters and Headquarters Company, and Company A of the 4th Battalion, 28th Regiment, California State Guard.
Source: US Army Corps of Engineers and History of the California State Guard