South Dakota is among the states with the lowest population density and is split by the Missouri River. East of this river is mostly residential areas and farming, with fertile soil that makes it a big agricultural producer. There are many ranches in the western part of South Dakota, and a big tourist destination. The state is home to Mount Rushmore, as well as the Black Hills, located in the southwest area of the state. The state experienced a gold rush in the 1890s when gold was discovered in the Black Hills area. Today, jewelry made from Black Hills gold is known the world over.