The Little Missouri National Grassland is the largest designated National Grassland in the United States and represents one of the best examples of intact native mixed-grass prairie in the United States. The Little Missouri National Grasslands occurs entirely within the Williston Basin, which has been a leading source of conventional oil and gas production since the 1950s. Recent advances in horizontal drilling and hydraulic fracturing (since 2000) have greatly increased energy extraction activities on the Little Missouri National Grassland. The objective of this assessment is to synthesize existing knowledge from peer-reviewed literature and administrative studies that describe the actual and potential impacts of oil and gas development on the biological resources of the Little Missouri National Grassland. The assessment focuses on how energy extraction activities may impact soils, vegetation, and wildlife, with specific reference to threatened and endangered species.