Museum specimens and literature records were used to determine the historical distribution and native status of redbelly dace in the Arkansas River Basin, Colorado. All specimens examined were southern redbelly dace (Chrosomus erythrogaster) and native status in the Arkansas River Basin was supported, in part, on the basis of a previously undiscovered specimen collected in 1913. Southern redbelly dace were documented in a geographically restricted area from near Canon City, Colorado, downstream to near Pueblo, and all locations were small tributary streams or off-channel ponds. The two remaining wild populations of southern redbelly dace in Colorado, and transplanted populations that originated from now extirpated populations, should be protected. Additional surveys should be conducted to determine if other populations exist in Colorado, which will better inform managers regarding future actions for the conservation of this species.