The Marble Mountain Wilderness is a 241,744-acre (978.30 km²) wilderness area located 60 miles (97 km) southwest of Yreka, California, in the United States. It is managed by the U.S. Forest Service and is within the Klamath National Forest in Siskiyou County. The land was first set aside on April 1931 as the Marble Mountain Primitive Area, which comprised 234,957 acres (950.84 km²). It was one of four areas to gain primitive status under the Forest Service's L-20 regulations that year. In 1964, it became a federally designated wilderness area when the U.S.