Fanning's Illustrated Gazetteer of the United States... (New York: Phelps, Fanning & Co., 1853), 331.
SANGAMON or SANGAMO COUNTY, situated in the central part of Illinois, and traversed by Sangamon river. Area, 900 square miles. Face of the country, even; soil, rich. Seat of Justice, Springfield, which is also the state capital. Pop. in 1830, 12,960; in 1840, 14,716; in 1850, 19,228.