The reported, natural distribution of Lepomis miniatus (Redspotted Sunfish) encompasses the Mississippi Valley and Gulf Slope drainages, but not the Cumberland River basin of Tennessee. We provide an account of 3 cataloged specimens collected from Mill Creek in the Cumberland River basin at Standing Stone State Park, TN. Review of previously unpublished records around Lake Barkley and Standing Stone Lake combined with collection of multiple specimens upstream and downstream of Standing Stone Lake suggest a naturalized population now exists 421 river km outside of the previously documented range. Range expansion in the Cumberland River basin is likely related to human introduction ultimately arising from stock contamination.