Fanning's Illustrated Gazetteer of the United States.... (New York: Phelps, Fanning & Co., 1853), 93.
COOPER COUNTY, situated in the central part of Missouri, on the south side of Missouri river. Area, 400 square miles. Face of the country generally level, with rich and fertile prairies. The alluvial soil along the streams is also of first rate quality. Seat of justice, Bonneville. Pop. in 1820, 6,959; in 1830, 6,019; in 1840, 10,848; in 1850, 12,950.