city on Mississippi River 35 mi (55 km) s.w. of Cairo, Ill.; agriculture, lumber, small manufacturing; founded as Indian trading post 1783; Confederate post 1861–62, Civil War battle fought there 1862; center of the most violent series of earthquakes in American history, Dec. 16, 1811, Jan. 23 and Feb. 7, 1812, followed by 1,874 severe aftershocks; quake felt from Canada to Gulf of Mexico; incorporated 1808; pop. 3,350