Monroe County, Illinois (Fanning's, 1853)
MONROE COUNTY, situated on the southwest boundary of Illinois, with the Mississippi river on the west, and the Kaskaskia river on the east. Area, 360 square miles. Seat of justice, Waterloo. Pop. in 1830, 2,000; in 1840, 4,481; in 1850, 7,679.
Fanning's Illustrated Gazetteer of the United States... (New York: Phelps, Fanning & Co., 1853), 231.