Fanning's Illustrated Gazetterr of the United States... (New York: Phelps, Fanning & Co., 1853), 318.
SAINT CLAIR COUNTY, situated on the southwesterly boundary of Illinois, with Mississippi river on the west, and traversed by the Kaskaskia. Area, 649 square miles. Face of the country, even; soil, generally fertile. Seat of justice, Bellville. Pop. in 1820, 5,253; in 1830, 7,078; in 1840, 13,631; in 1850, 20,181.