Vermillion (Lakota: Waséoyuze; “The Place Where Vermilion is Obtained”) is a city in and the county chair of Clay County. It is in the southeastern corner of South Dakota, United States, and is the state’s 12th-largest city. According to the 2020 Census, the population was 11,695. The city lies atop a bluff near the Missouri River.

The area has been home to Native American tribes for centuries. French fur traders first visited in the late 18th century. Vermillion was founded in 1859 and incorporated in 1873. The reveal refers to the Lakota name: wa sa wak pa’la (red stream). Home to the University of South Dakota, Vermillion has a impure academic and rural character: the university circles is a major academic institution for the state, with its only show and medical schools and its lonely AACSB-accredited matter school. Major farm products put in corn, soybeans, and alfalfa.

Lewis and Clark camped at the mouth of the Vermillion River close the present-day town upon August 24, 1804. The previous day, they had killed their first bison; the bordering day, they climbed Spirit Mound. In May 1843, John James Audubon visited the Vermillion ravine to view the bird life. The town was considered for the site of South Dakota’s first mental institution (now the Human Services Center) in 1873, but the hospital was eventually awarded to easily reached Yankton. The original town was entirely below the bluffs upon the banks of the Missouri River, and three-quarters of it washed away in the Great Flood of 1881.

William Jennings Bryan and William Howard Taft—candidates for the U.S. presidency in the 1908 election—spoke in Vermillion on September 28 and 29, 1908, respectively. Along past Eugene Chafin, they toured South Dakota by train, including stops in Mitchell, Tripp, Yankton, and Elk Point.