During July through October, 1990, the Illinois Environmental Protection Agency and the Illinois Department of Conservation conducted an intensive survey of the Vermilion River basin. The Vermilion River drains approximately 1331 square miles primarily in LaSalle and Livingston counties along with small portions of Ford, McLean, and Woodford counties before flowing into the Illinois River near Oglesby, Illinois. The survey consisted of 11 stations on the Vermilion River and 19 stations on fifteen tributaries. Data collected at each site included fish and macroinvertebrate communities, instream habitat, water and sediment chemistry. Fish tissue samples were collected when appropriate species were available. A total of 58 fish species and two hybrids were collected in the Vermilion River basin. Fish samples from Mud Creek included the greater redhorse (Moxostoma valenciennsi), a state endangered species, not previously recorded from this basin.