New opportunities for extensive research on Windmiller sites in California have been scarce in the last few decades. In addition, new methods are available for analyzing human remains which have yet to be applied to available collections. This paper presents new information on both fronts with an analysis of strontium isotope ratios (86Sr/87Sr) in human teeth and bone samples from the recently excavated population at CA-CCO-548. The data represent a snapshot of the composition of a Windmiller population and provide information for reconstructing migration and residence patterns as well as specific analyses of migration and group composition.