South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Humans have inhabited the area for several millennia, with the Sioux becoming dominant by the early 19th century. In the late 19th century, white settlement intensified after a gold rush in the Black Hills and the construction of railroads in the east. This settlement triggered a number of Indian Wars, ending with the Wounded Knee Massacre in 1890.