With more than 2 million specimens in over 56,000 catalogued lots, the ichthyology collection houses the largest and most comprehensive collection of fishes from Oklahoma. One of the collection’s greatest strengths is an extensive sample of species from the lower Great Plains, particularly from Oklahoma streams and reservoirs. Under the direction of A. I. Ortenburger, specimens were collected during expeditions in the 1920s. Other periods of extensive collecting include the 1950s, 1960s and 1980s. The collection grew during the 1990s thanks to area conservationist Jimmie Pigg and during the early 2000s due to the efforts of the Department of Environmental Quality who continued Pigg’s work. The availability of these long-term samples of specimens from statewide sites provides an important opportunity to assess natural variation in fish communities. We continue to add to the collection’s geographic diversity through ongoing research conducted by curators, professional staff, students and associates.