Surveys were performed to examine the diversity of Ephemeroptera and Plecoptera in selected lakes in Glacier National Park, Montana, and to generate data for use by the National Park Service. Shallow shoreline sites were sampled by disturbing the bottom and examining the substratum. Published records and previously collected reference specimens were examined. Data were obtained from a total of 29 lakes, but 3 yielded no mayflies or stoneflies. Twelve genera and 21 species of Ephemeroptera, and 11 genera and 5 species of Plecoptera, were found. Most lakes sampled had a diverse fauna of both orders.