During the Great Depression of the 1930s, Lassen County would have two Civilian Conservation Camps, better known as the CCC. One was located at Halls Flat in western Lassen County, just north of Poison Lake. The other was Secret Valley, thirty-five miles northeast of Susanville, which one can see remnants from Highway 395 when driving north.
The Halls Flat CCC camp was established in 1933 and shut down in 1942. The camp provided a lot of manpower for the Lassen National Forest. Among the work done was grazing studies, range habitat improvement and some logging of pine beetle infested trees in the nearby Blacks Mountain Experimental Forest.