The Mimbres Valley and the NAN Ranch Ruin are located in southwest New Mexico, near Silver City. According to Harry Shafer, 'The site was named after the ranch cattle brand, NAN, by C.B. Cosgrove, who, with the help of his son, Burt Jr., in 1926, was among the first to excavate at the site.' After more than twenty years of excavating the large Classic Mimbres pueblo site overlying a pithouse village in the Mimbres Valley and analyzing the finds, Shafer argues there was a fascinating restructuring of Mimbres culture and society. The catalyst, Shafer theorizes, was the implementation of irrigation agriculture about AD 850-900. The social reorganization resulted in a number of material changes, including substantive shifts in architecture from pit houses to surface pueblos, the establishment of lineage-based residences, lineage cemeteries, and new ritual activity and behavior that resulted in the architecture, mortuary behavior, and decorated ceramics.