We present a comprehensive genetic investigation of Late Neolithic (LN) and Early Copper Age (ECA) populations living in the Carpathian Basin, leveraging whole genome data from 125 previously unreported individuals. Using population genetics, kinship analyses and the study of networks of identity-by-descent haplotype segment sharing, we elucidate the social and genetic dynamics of these communities between 4800-3900 cal BCE. Despite changes in settlement patterns, burial practices, and material culture, we document a high degree of genetic continuity. While one set of individuals we analyzed from a large community cemetery was genetically diverse, another site was more homogenous and closed, with numerous consanguineous relationships and evidence of patrilineality and patrilocality. These results document radically different kinship systems in contemporaneous ECA communities using similar material culture and living only about 100 km apart.