The eastern part of the Sawtooth National Recreation Area contains several hundred prospects and mines, some of which have produced substantial quantities of ore. An intensive investigation indicated that much of the area has a probable or substantiated mineral-resource potential for many metallic minerals. Because of recorded past production, known deposits, and the likelihood of finding additional deposits, much of the area, particularly that part underlain by structurally contorted, undifferentiated metasedimentary rocks, has a probable or substantiated mineral-resource potential. The geologic terrane precludes the occurrence of fossil fuel resources.