Mortuary Practice Among Prehistoric North Americans: Plains Region, is Volume II of the five volume set entitled PRE-COLUMBIAN BURIAL RITES. Twelve years of research that covered North America between the Rockies and the Appalachians provided a comprehensive multi-regional database consisting of 97,821 deceased individuals from 3,678 prehistoric burial sites. From that database I formulated a Plains region database consisting of 13,104 deceased individuals from 1,229 burial sites within Montana, Wyoming, Colorado, North and South Dakota, Nebraska, Kansas, Oklahoma, and Texas. Built on the premise that analysis of mortuary practice is a valuable tool in the examination of prehistoric cultural entities, the variability and consistency of burial traits on the Plains establishes a pattern of conservative behaviors that are definitive in the detection of cohesive cultural groups. Burial traits that were thoroughly investigated included: MNI (minimum number of individuals), cremation, secondary inhumation, primary inhumation, bundling, position of deposition, placement, age and sex, artificial cranial flattening, time line, cultural affiliation, mortuary furniture specifics, head direction, mortuary facility, and in-site burial location. It was ascertained that multiple cultural populations exhibited ritually-oriented and conservatively-grounded patterns of behavior that differentiated their society's practice of burial ideology. The ritual patterns also indicated that over long spans of time, societal disruption occurred when cultures adapted to internally changing viewpoints, sometimes exacerbated by changing climate and geographic environments. Because the North American plains is a vast territory the detailed analysis of prehistoric burial characteristics was a complex and intricate web of sub-regional population movements through time that documented with some clarity how the different cultural groups dealt with the disposal of the deceased population on the prehistoric North American plains.