Fanning's Illustrated Gazetteer of the United States.... (New York: Phelps, Fanning & Co., 1853), 37.
BEAVER COUNTY, situated in the western boundary of Pennsylvania, and traversed by Ohio and Beaver rivers. Length, about 40 miles; mean breadth, 15; with an area of 600 square miles. The face of the country is broken and hilly; the soil generally fertile, well wooded and watered. Seat of justice, Beaver. Pop in 1820, 13,34O; in 1830, 24,183; in 1840, 29,368; in 1850, 26,689.