city, seat (1818) of Cooper county, central Missouri, U.S. It lies along the Missouri River, 27 miles (43 km) west of Columbia. Settled in 1810 (by Kentuckians, among others) and named for Daniel Boone, Boonville was enlarged as a fort during the War of 1812 and became an important trading post on the river and the Santa Fe Trail. In the mid-19th century there was a large influx of German immigrants. During the American Civil War the first battle in the state was fought near Boonville, and the victory there by Brigadier General Nathaniel Lyon's Union troops is credited with helping to establish Union control over the state. Thespian Hall (1855–57), considered the oldest working theatre west of the Alleghenies, was used during the war as a supply depot, barracks, and hospital. Boonville is now an agricultural trade centre. Manufactures include modular homes and heating and cooling components. Four Hopewell Indian burial mounds dating from 100 BC to AD 500 are preserved within Harley Park, located on the river bluffs. Arrow Rock and Boone's Lick state historic sites are nearby. The Big Muddy Folk Festival and the Missouri River Festival of the Arts are annual events. Inc. village, 1839; city, 1896. Pop. (2000) 8,202; (2005 est.) 8,669.