YANKTON, a city and county-seat of Yankton co., S. D.; on the Missouri river, and on the Great Northern, the Chicago, Milwaukee and St. Paul, and the Chicago and Northwestern railroads; 61 miles N. W. of Sioux City, Ia. Here are Yankton College (Cong.), a high school, the State Hospital for the Insane, waterworks, electric lights, National, State, and savings banks, and daily, weekly, and monthly periodicals. It has an extensive general trade, and is the supply depot for the Indian agencies and military stations along the Upper Missouri. There are planing mills, large Portland cement works, flour mills, foundry, woolen mill, pork packing establishments, etc. Pop. (1910) 3,787; (1920) 5,024.