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Located in the tallgrass prairie ecoregion, South Dakota's Prairie Coteau is a unique geologic formation that still retains a relatively large amount of native tallgrass prairie and provides habitat for numerous species, including the USFWS proposed threatened species, the Dakota skipper butterfly (Hesperia dacotae). However, prairie remnants continue to vanish due to cropland conversion and degradation from invasive species. In order to best inform a conservation plan for the Dakota skipper and other endemic prairie species, the identification of high quality prairie habitat is urgently needed. The objective of this study was to delineate and classify upland prairie within a 58,275-ha region of South Dakota's Prairie Coteau chosen for its high concentration of Dakota skipper occurrence records. All grasslands within the study area were identified using aerial imagery to create an ArcGIS layer to guide on the ground field surveys and vegetation sampling. During field surveys, grassland condition was ranked and delineated in ArcGIS. Vegetation sampling used 10-m X 10-m relevé plots subjectively placed in uniform, native plant communities, according to Minnesota County Biological Survey protocol. Sixty-eight plots were sampled from July 8 to August 20, 2013 and 2014. Within each plot, cover by species within three strata was estimated using Braun-Blanquet cover classes and ecological site factors (e.g. elevation, aspect) and management regime (grazed, hayed or rested) were recorded. NMS ordination of relevé plots produced a 3-dimensional solution with 52.1% and 18.5% of variation being explained by axes 1 and 2 respectively. Axis 1 was found to represent a moisture gradient while management type was found to influence the second axis. Agglomerative hierarchical clustering was applied to classify the plant communities. The classification will enable mapping, assessment and inventory of habitat for the Dakota skipper and other upland prairie species on South Dakota's Prairie Coteau.