“In the early 1900’s railroad workers and miners of the area carved out homes in the solidified volcanic ash. Dublin Gulch was inhabited on and off up until the mid-1970s. Miners, hobos, hippies, and derelicts all called these caves home. When one person moved out or died, another moved in.
Rumor has it that several Manson family members lived in these caves after being kicked out of Barker Ranch by Charles Manson.” (https://www.daytrippen.com/dublin-gulch-ghost-town-miners-caves/)