Empires have transformed political, social, and environmental landscapes in the past and present. Although much research on archaeological empires focuses on large-scale imperial processes, we use biogeochemistry and bioarchaeology to investigate how imperialism may have reshaped regional political organization and regional migration patterns in the Wari Empire of the Andean Middle Horizon (ca. AD 600–1000). Radiogenic strontium isotope analysis of human remains from the site of Beringa in the Majes Valley of southern Peru identified the geographic origins of individuals impacted by the Wari Empire. At Beringa, the combined archaeological human enamel and bone values range from 87Sr/86Sr = 0.70802 − 0.70960, with a mean 87Sr/86Sr = 0.70842 ± 0.00027 (1σ, n = 52). These data are consistent with radiogenic strontium isotope data from the local fauna in the Majes Valley and imply that most individuals were local inhabitants, rather than migrants from the Wari heartland or some other locale. There were two outliers at Beringa, and these “non-local” individuals may have derived from other parts of the South Central Andes. This is consistent with our understanding of expansive trade networks and population movement in the Andean Middle Horizon, likely influenced by the policies of the Wari Empire. Although not a Wari colony, the incorporation of small sites like Beringa into the vast social and political networks of the Middle Horizon resulted in small numbers of migrants at Beringa. Am J Phys Anthropol, 2011. © 2011 Wiley-Liss, Inc.