Communal pronghorn procurement in Northwestern Plains during prehistoric times is scantily expressed in the archaeological record. This chapter presents the analysis of faunal remains from the 1000-year-old Lost Terrace pronghorn processing site. Lost Terrace, a single-component site, is situated along the Upper Missouri National Wild and Scenic River in north-central Montana. Analyses of Lost Terrace pronghorn bones and other materials are still in progress. In southwestern Wyoming, on the boundary between Northwestern Plains and Great Basin, sites with the bones of pronghorns as exclusive, or numerically dominant, prey are relatively abundant in Late Prehistoric times. During the time between death of Lost Terrace pronghorns and site excavation, the bone assemblage could have been altered by taphonomic agencies. The age composition of the pronghorn population was determined by analysis of dentary tooth eruption and wear, and from fetal bones. Three stages of butchering can leave cut marks on bones: skinning, dismembering articulations, and removing meat.