Halls Flat is a location in Lassen County, California on the Western Pacific Railroad 10.5 miles south-southwest of Little Valley, at an elevation o…Halls Flat is a location in Lassen County, California on the Western Pacific Railroad 10.5 miles south-southwest of Little Valley, at an elevation of 5705 feet. It was the site of a Civilian Conservation Corps camp, and in the 1940 became the location of a lumber camp named after Paul Bunyan, which operated to the end of the decade.