16-42 inches. Slender black or brown snakes with a white, yellow or orange stripe down the back and a pale stripe on each side covering the 3rd and 4th scale rows above the ventral plates; underside whitish; scales keeled and in 19 rows. Unlike the eastern ribbon snake, the white parietal spot on top of the head is distinct, and there is no brown coloration on the outer edges of the ventral plates.
Western ribbon snakes occur in grassland and woodland habitats, often in the vicinity of water sources, around swamps and in marshes. Areas with ample sunlight are preferred. They give birth to 4-34 young.
Throughout Louisiana except Washington and northern St. Tammany parishes.