The city of Teotihuacan (AD 1–550) was a major multiethnic urban center that attracted migrants from as far away as west Mexico and the Maya region. Past research in the Tlajinga district at Teotihuacan using oxygen isotopes from human remains estimated that nearly 30% of the population of Tlajinga 33, a single apartment compound, were migrants. This study takes a dual-isotope approach (87Sr/86Sr and δ18Op) to reevaluate the proportion of in-migration at Tlajinga and includes data from two additional apartment compounds, Tlajinga 17 and 18 (n = 23). New results indicate that migrants comprised ~45% of the Tlajinga population. Previously acquired radiocarbon dates combined with mortuary and isotope data suggest that immigration to Tlajinga was highest during the first centuries of compound occupation. Nevertheless, migration was a continual process throughout its history. Additionally, a new finding suggests that residents of Tlajinga 33 ingested foods with higher 87Sr/86Sr ratios than did those of Tlajinga 17 and 18. We hypothesize that the incorporation of imported lime for the nixtamalization process skewed the 87Sr/86Sr ratios of human remains, a potentially important finding for future studies at Teotihuacan.

San José 520 is a Classic period hamlet of single-family residences in the urban periphery of Teotihuacan, just beyond the southeast edge of the city. Three burial features were associated with one of the residences, AF2. One of the features contained the burial of a single adult, another the successive burials of eight adults and one neonate, and the third held a neonate. We analyzed 29 bone and enamel samples from the adults for bioapatite phosphate oxygen-isotope composition; we also considered isotopic data for another five bone samples analyzed in a separate project. The isotopic results suggest a pattern of birth in the Teotihuacan region and then movement in early childhood to a “relocation” region, the geographic location of which is unknown. Later, probably in adolescence, the individuals returned to live, and eventually die, in San José 520. Without knowing more about the occupation of the relocation region, it is difficult to say what concerns or beliefs underlay this unusual but long-established settlement system.