This data release comprises a dataset that contains sample collection information and microsatellite genotypes, and another dataset that contains single nucleotide polymorphism (SNP) genotypes with sample collection information for populations of white-tailed ptarmigan across the species' range. There is also an additional file (accession numbers.xlsx) linking samples to accession numbers in Genbank. This data was collected in order to address the following: The delineation of intraspecific units that are evolutionarily and demographically distinct is an important step in the development of species-specific management plans. Neutral genetic variation has served as the primary data source for delineating units for conservation, but with recent advances in genomic technology, we now have an unprecedented ability to utilize information about neutral and adaptive variation across the entire genome. Here, we use traditional genetic markers (microsatellites) and a newer reduced-representation genomic approach (single nucleotide polymorphisms) to delineate distinct groups of white-tailed ptarmigan (Lagopus leucura), an alpine-obligate species that is distributed in naturally fragmented habitats from Alaska to New Mexico.