Fanning's Illustrated Gazetteer of the United States.... (New York: Phelps, Fanning & Co., 1853), 299.
POSEY COUNTY, situated at the southwest corner of Indiana, with Ohio river on the south, and the Wabash on the west. Area, 450 square miles. Seat of justice, Mount Vernon. Pop. in 1820, 4,061; in 1830, 6,546; in 1840, 9,683; in 1850, 12,550.