The data includes measured data from Ecoregions 69 and 70 in West Virginia. Paired biological and chemical grab samples are included. These data were used to estimate SC extirpation concentration (XC95) for benthic invertebrate genera. Also included are cumulative frequency distribution plots, scatter plots fitted with generalized additive models, and biogeographical maps of observations of each genus. The metadata and full data set is available in Supplemental Appendices S4 and S5, respectively. The output of 176 XC95 values from Ecoregions 69 and 70 are provided in Supplemental Appendix S6. Supplemental Appendix S7 depicts the probability of observing a genus for discrete ranges of SC. Supplemental Appendix S8 depicts the proportion of occurrence of a genus for discrete ranges of SC. Supplemental Appendix S9 shows the biogeographic distributions of the genera included in the data set. We also discuss limitations of this method to help avoid misinterpretations and inferential errors. A data dictionary is provided in Cond_DataFileColumnMetada-20161221. This dataset is associated with the following publication: Cormier, S., L. Zheng, E. Leppo, and A. Hamilton. Step-by-Step Calculation and Spreadsheet Tools for Predicting Stressor Levels that Extirpate Genera and Species. Integrated Environmental Assessment and Management. Allen Press, Inc., Lawrence, KS, USA, 14(2): 174-180, (2018).