Eighty-one species of butterflies and two-hundred and thirty-seven species of moths were identified from Fort Indiantown Gap, a National Guard training facility in south-central Pennsylvania. The Lepidoptera found here include the last remaining population of Speyeria idalia idalia (eastern regal fritillary), as well as the rare Callophrys irus (frosted elfin), Hesperia leonardus (Leonard's skipper), Datana ranaeceps (hand-maid moth), Zale sp. 1 nr. lunifera (Pine Barrens zale), and Anisota stigma (spiny oakworm moth). This habitat has a large and diverse Lepidoptera fauna, most likely due to periodic disturbance in some areas, conservation efforts to maintain native grassland, and a diverse plant community.