This dataset includes the geographic location (lat/lon) for 15,136 plots, as well as the herbaceous species richness, climate, soil pH, and other variables related to the plots. This dataset is associated with the following publication: Simkin, S., C. Clark , W. Bowman, E. Allen, J. Belnap, and L. Pardo. Conditional vulnerability of plant diversity to atmospheric nitrogen deposition across the United States. PNAS (PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES). National Academy of Sciences, WASHINGTON, DC, USA, 113(15): 4086-4091, (2016).