Riverside Bluffs is a Loess Hills prairie area in Sioux City. The area was acquired in 1992 with assistance from the Woodbury County Conservation Foundation and a Resource Enhancement and Protection (REAP) Grant. The 135-acre preserve is divided into two sections on either side of West 19th Street between Military Road and Riverside Park in west Sioux City. Access is gained through Kirk Hansen Park or the trail head located on West 19th Street.

Many birds, mammals, reptiles and insects make the Riverside Bluffs their home. Rare or habitat-restricted butterflies in the area include the Ottoe skipper, regal fritillary, Pawnee skipper, and dusted skipper.

The area is restricted to foot traffic only.