Astragalus magdalenae var. peirsonii (Fabaceae - Peirson’s milkvetch)  is a perennial herb that is native to dune habitats in southern California USA, Baja California, MX. This species is presently listed as Threatened under the Federal Endangered Species Act (ESA) and Endangered under the California ESA. Throughout the species range, habitat fragmentation and degradation, impacts from OHV use, low reproduction rates, and climate change have been documented as threats. Here we present new results of a robust, range-wide population genomic study for this endangered species in California. Specifically, we will address genetic structure, genetic diversity, in-breeding, and current patterns of gene flow within and among populations. We will also discuss how these results will inform future management and restoration efforts to protect this imperiled species.