Conservation efforts are frequently hampered by uncertainty regarding species' distributions. Range maps as representations of species distributions are known to overestimate the area occupied by the species, with significant implications for the prioritization of conservation efforts among species. We investigate the disparity between extent of occurrence (i.e., “range”) and area of occupancy of a population or species and discuss its implications. Using as a test group a community of subalpine butterflies (Lepidoptera: Papilionoidea), we estimated range occupancy based on three levels of analysis: two field guides with differing mapped resolution of range and microdistribution data collected in the vicinity of the Rocky Mountain Biological Laboratory, near Crested Butte, Gunnison County, Colorado. We conclude butterfly range occupancy across species is low and variable, ranging from 1% to 37% among species present in our sample. A large proportion of species identified as present by range maps in both field guides (70%) were absent from our sample and we present species-specific expert opinion regarding their absence. We demonstrate potential practical and conceptual challenges inherent in the use of range maps to assess endangerment and conservation priority.