Isotopic assays, including stable carbon, stable oxygen, and radiogenic strontium were measured for 37 individuals from the Talgua cave ossuaries to understand human movement and mortuary practice during Formative Period Honduras. Likelihood assignment models demonstrated that the individuals had diverse childhood geographic origins within the surrounding valleys. This shows that different kin or ethnic groups from diverse geographic origins were utilizing the ossuaries. Five possible ‘non-local’ individuals were identified from the radiogenic strontium and stable oxygen isotope datasets, suggesting minimal human movement into northeast Honduras from outside Lower Central America. The low number of ‘non-local’ individuals at Talgua Caves also suggests that trade items were acquired by down-the-line exchange processes rather than through a long-distance trade connection. This type of trade network and bioarchaeological evidence of limited ‘non-local’ individuals at Talgua Caves suggests the surrounding region was culturally distinct from Mesoamerica during the Formative Period.