Some of the worst tornadoes in U.S. history include: the Tri State tornado, which struck Missouri, Indiana, and Illinois in 1925, killing 695 people and injuring 2,027; the 1840 Natchez tornado struck Mississippi, killing 317 people and causing injuries to another 109; and the St. Louis/East St. Louis tornado of 1896 killed 296 people and injured 1,000.