Abstract: The present disclosure provides methodology to generate one or more local ancestry inferences (“LAIs”) from genomic information for a target individual having a local ancestry that is at least partially unknown or unconfirmed. The LAI determinations herein can be generated using a LAI determination engine operational with a population reference database comprising a plurality of subpopulation reference datasets derived from genomic information obtained from collections of non-admixed individuals having known or determined local ancestry origins. Synthetic genomic data can also be generated to provide subpopulation reference datasets when actual genomic data having known local ancestry origin is not available. The methodology herein has utility in generation of polygenic risk scores for a target individual, among other things.