Setodes truncatus n. sp. is illustrated and described herein based on specimens collected from 2 adjacent watersheds of the Huron Mountains in northern Michigan (USA). Both known populations inhabit undisturbed sandy rivers. Males of S. truncatus appear most similar to those of S. incertus (Walker) but can be separated based on their short and truncate inferior appendages and by other differences in the genitalia. The larva and female both remain unknown. A revised key to males of the 10 North American species of Setodes is provided.