Did You Know? Iowa's natural vegetation is the Tallgrass prairie and Savanna while the topography of the state is gently rolling plains. Loess hills lie along the western border of the state, some of which are several hundred feet thick.[4] In the northeast, along the Mississippi River, is a section of the Driftless Zone, which in Iowa consists of low rugged hills covered with conifers—a landscape not usually associated with this state. The point of lowest elevation is Keokuk in southeastern Iowa, at 480 feet (146 m). The point of highest elevation, at 1,670 feet (509 m), is Hawkeye Point, located in a feedlot north of Sibley in northwest Iowa. The mean elevation of the state is 1,099 feet (335 m). Considering the size of the state at 56,271 square miles (145,743 km˛), there is very little elevation difference.