Up to date research on the historical and current distribution of the least darter (Etheostoma microperca) in Ohio is not available, despite its status as a Species of Concern. Using a dataset of 229 recorded occurrences, we compared 20th and 21st century presence/ absence of least darter in Ohio to detect changes in distribution and evaluate the need for conservation measures. We added 11 recent surveys for streams that lacked 21st century data. Before 2000 the least darter was known from 44 streams in 18 counties across the glaciated portion of Ohio. This decreased to 37 streams in 14 counties in surveys from 2000 to 2013 considering only temporally spaced collections (e.g., at least two collections per location – one from the 20th and one from the 21st century). Two streams added E. microperca populations since 2000. However, in spite of continued monitoring, nine streams lost populations including the disappearance from counties in its Northeastern Ohio range. Farm ditches with ample vegetation were common locations where least darters were encountered. Because least darters are associated with vegetated habitat throughout their life history, such ditches may serve as important habitat for this species if plant communities are maintained. E. microperca remains vulnerable in Ohio, and we recommend continued monitoring.