Historic Places In Yankton County Yankton College Historic District 12 and Douglas Sts., Yankton Western Portland Cement Plant West of Yankton, Yankton Yankton Historic Commercial District Roughly bounded by 2nd, 4th, Pine and Broadway, Yankton Yankton Carnegie Library 4th and Capitol Sts., Yankton Yankton High School Historic District Yankton FORMER LISTINGS Walnut Street Bridge Walnut Street over Marne Creek, Yankton Yankton College Conservatory Yankton College campus, Yankton 32vYANKTON COUNTY GUIDE 2018 Yankton County Courthouse 3rd St. and Broadway, Yankton (Demolished in June 2013)