I did find this information from Western ribbon snake photo - Thamnophis proximus - G115107 - ARKive

Range

The western ribbon snake occurs from Ohio, Indiana, Illinois and southern Wisconsin in the central United States, west through the Great Plains to Kansas, Nebraska and Oklahoma, and south into Central America, as far as Costa Rica.

The subspecies T. p. proximus occurs in the United States, while T. p. diabolicus and T. p. orarius range from the U.S. to Mexico. T. p. rubrilineatus is confined to the Edwards Plateau of central Texas, while T. p. rutiloris occurs from Mexico to Costa Rica, and T. p. alpinus is restricted to high elevations in central Chiapas, Mexico.