Hannibal, city (1990 pop. 18,004), Marion and Ralls counties, NE Mo., on the Mississippi River; inc. 1845. It is a river port and shipping center. Industries include meat canning, printing, and the manufacture of boats, electronics, and wood and metal products. Agriculture and tourism are also important. Hannibal is famous as the boyhood home of Mark Twain; his house has been preserved, and a museum, a statue, a lighthouse, and a bridge across the Mississippi commemorate him. The famous Mark Twain cave is nearby. Hannibal-LaGrange College is also located there.