 In 1855, Thespian Hall opened, and today claims to be the oldest continuously running theatre west of the Allegheny Mountains.More than 400 buildings (most in 14 separate historical districts) are listed on National Register of Historic Places listings in Cooper County, Missouri.During the American Civil War, the community was fought over and held by both Union and Confederate forces, beginning with the Battle of Boonville on June 17, 1861 (a month before the First Battle of Bull Run) which gave the Union control of the Missouri River.