Although many limnological surveys have been conducted on major reservoirs in the southcentral United States, little is known about the physicochemical and biotic properties of small impoundments, which constitute the majority of aquatic systems in this part of the country. The major limnological characteristics of Sangre Isle Lake, a small impoundment in northcentral Oklahoma, U.S.A., were evaluated during 1982–1983. Collectively, the data indicate that this lake has limnological features closely resembling those of a typical small, natural eutrophic lake.