This study’s research question and hypotheses are derived from early anthropological and social theories, which suggest that the sexual division of labor is correlated to postmarital residence patterns. Those studies hypothesized that matridominant subsistence favors matrilocality while patridominant subsistence favors patrilocality. Advancements in archaeometry, particularly isotope analysis of human skeletal tissues, permit archaeologists to generate nuanced data sets to investigate ancient diet and mobility patterns. Stable isotope analysis provides evidence of paleomigration and diet for individuals, can distinguish between site- and individual-level residential and dietary patterns, and permits comparison between male- and female-mobility and dietary patterns. The original objective of this dissertation research was to investigate the relationship between the sexual division of labor with postmarital residence for Early Period (c. 5000–2400 cal BP) populations from archaeological sites CA-SAC-107 and CA-SJO-68 in central California, using five different isotopic systems (δ13C, δ15N, δ34S, δ18O, and 87Sr/86Sr). While new radiocarbon dates, reported here, reveal assays ranging from 4497 ± 27 to 3132 ± 24 RCYBP at CA-SJO-68, as expected, those from CA-SAC-107 range from 3427±26 to 135±20 RCYBP and thus necessitated re-evaluation of chronological patterns. Paleodietary reconstruction using δ13C and δ15N of human bone collagen and δ13C of bone apatite largely support expectations from archaeofaunal, paleobotanical, and artifactual evidence from central California. Isotopic indicators of diet reveal that the CA-SAC-107 population foraged within a C3-terrestrial food web with minimal sex differences in dietary behaviors. Confounding variables, including small sample sizes and the temporal bias of sampled elements, limited interpretation of sex-biased mobility and postmarital residence in the Early Period using δ34S, δ18O, and 87Sr/86Sr at CA-SAC-107. However, isotopic results relating to human geolocation at the site are generally consistent with marriage endogamy and increasing sedentism over time. Paleodietary reconstruction at CA-SJO-68 using δ13C and δ15N of human bone are consistent with high input of freshwater-riverine resources and demonstrate that males typically consumed higher-trophic-level resources than females. Results of paleomobility analysis and interpretation of postmarital residence using δ34S, δ18O, and 87Sr/86Sr at CA-SJO-68 are consistent with endogamous marriage practices and greater mobility for males, particularly during late adolescence.