The Pine Ridge escarpment in northwestern Nebraska exhibits a unique topography and flora in relation to the general characteristics of the mixed prairie of western Nebraska. Because of this influence, interesting populations of Rhopalocera exist. In all, 100 species of butterflies were associated with the escarpment, 89 of which have been recently collected. Data include flight periods, collection localities, collection dates, adult nectar sources, and ecological notes for species collected during the summers of 1960 to 1965. Results indicate that butterflies associated with the Pine Ridge show a greater affinity to populations of the Rocky Mountains and Black Hills than to eastern populations.