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The use of fire in South Dakota's mixed-grass prairie has little documented publications on impacts. The ability to use fire as a management tool in the Dakotas could provide more cost-effective ways to control unwanted species like crested wheatgrass (Agropyron cristatum (L.) Gaertn.) while increasing native diversity and livestock grazing distribution. In 2008, frequency, density, phytomass, and basal cover were collected on 142 plots using two perpendicular 150m transects in the Grand River National Grasslands, Perkins County, South Dakota, USA. In April 2013, a wind-driven wildfire quickly spread over several pastures monitored in 2008. The same methods were replicated to compare cool- and warm-season graminoids, forbs, crested wheatgrass, and other introduced species on sandy and shallow sandy ecological sites. For sandy sites, both native dominated and crested wheatgrass dominated sites were chosen, three from within the burned area and three like plots within an unburned area for a total of 12 plots. On the shallow sandy sites, only native dominated sites were chosen, three burned and three unburned. Using a Student's T-test, native, cool-season graminoids and crested wheatgrass were compared between years and then between burned and unburned sites. Burned and unburned treatments in the same year on the same ecological sites showed no differences (p>0.05) between cool-season graminoids and crested wheatgrass. Several changes were seen between years. Native shallow sandy unburned sites had more (p<0.05) Canada bluegrass (Poa compressa L.) from 2008 to 2013. There was a decrease (p<0.05) in sun sedge (Carex inops L.H. Bailey spp. heliophila (Mack.) Crins) presence on sandy crested wheatgrass sites burned and unburned. There was also a decrease (p<0.05) in threadleaf sedge (Carex filifolia Nutt.) presence from 2008 to 2013 on native sandy unburned sites. It may take more growing seasons to see the true effects of the wildfire on species frequency and density.