The apple (Malus domestica) is a historically and contemporarily significant economic resource in the United States, comprising a $2.2 billion industry. Modern domesticated apples are descendants of two distinct lineages of Malus species, M. sylvestris and M. sieversii, and show a wide range of geographic distribution. Consequently, their extreme heterozygosity has made the global population of domesticated apples very genetically diverse. Apples were brought to Boulder County for cultivation in the 1860s, and some subsequently became feral in open space areas. Climate change may result in the loss of historic, heirloom strains adapted to local conditions, accelerating the need to understand the genetic diversity of historic and feral apple trees in Boulder County. Of apple cultivars recorded in Boulder County within the last century, few have genomic data available. We gathered whole-genome sequence data from five varieties of apple cultivars that are known to be historically found in Boulder County with 15 whole-genome sequences from other Malus varieties of domestic apples and crabapples. To analyze the population structure, we used the R package PcAdapt and the UNIX software Ohana, both newer tools which have not been used for this kind of analysis for M. domestica. (last sentence below)