Mammoth and Salts caves in west-central Kentucky were Intensively mined for gypsum and other sulfate minerals during the Early Woodland period (ca. 1000–200 B.C.). I propose that this mining was part of a larger ritual performance assodated with the initiation of adolescent males into adulthood. Drawing on ethnological literature, I suggest that, beginning in the Early Woodland, caves became integral settings for male rites of passage. This argument is based on (1) ethnographic examples of male initiation that invokes the use of caves for secrecy and seclusion, (2) fecal steroid analysis that indicates exclusive male activity, (3) medicinal use of cave minerals as a purgative, (4) evidence of sensory deprivation and possible use of psychotropic substances to heighten states of consciousness, and (5) collection of gypsum as a symbolic marker of transitional rites. Using an institutional economic approach, I further suggest that Early Woodland ritual cave use is correlated with the formation of new social institutions and new forms of property relations stemming from the emergence of horticultural economies in the Eastern Woodlands.