Large-mammal communal hunting strategies were prevalent in the Rocky Mountains from the Middle Archaic (5.7–3.2 ka) through the Late Prehistoric (1.5-0.2 ka) periods. The prevalence of bison trapping sites in the highlands indicates the cooperation of large labor forces for the construction and operation of communal hunts. Despite the potential of these sites for evaluating hypotheses of cooperative behavior, the cultural dynamics remain unclear. The Willow Springs Bison Pound is a multi-component communal hunting site in the Laramie Basin, Wyoming. High-density projectile-point and bone assemblages indicate sporadic use spanning a millennium from 3.2–0.2 ka. This study evaluates whether variation in the projectile point assemblage represents one or more cultural groups. In identifying the number of cultural groups, we furthermore seek to identify their territorial origins and the extent to which cooperation networks extended into the lowlands. We identify the presence of both atlatl and archery technology. However, the analysis reveals two culturally distinct point forms that cross-cut the two projectile technologies. These results are consistent with a multi-group hunting hypothesis. Preliminary raw material analysis suggests a strong highland presence with some lowland participation. These results inform our understanding of cooperative dynamics among Late Prehistoric bison hunters in the Rocky Mountains.