This section is from "The American Cyclopaedia", by George Ripley And Charles A. Dana. Also available from Amazon: The New American Cyclopędia. 16 volumes complete..
Allegheny, a S. W. county of Pennsylvania; area, 750 sq. m.; pop. in 1870, 262,204. Near the centre of the county the Ohio is formed by the confluence of the Alleghany and Monongahela rivers. The Youghiogheny and several creeks also drain it. Near the rivers the surface is broken into ravines; most of the upland is hilly and very picturesque. Nearly all of the county is arable. The productions in 1870 were 325,331 bushels of wheat, 674,916 of corn, 1,111,269 of oats, 78,372 of rye, 69,946 of barley, 769,144 of potatoes. 308,475 lbs. of wool, 1,223,744 of butter, and 64,730 tons of hay. Bituminous coal is found in the county, and iron, glass, wool, etc, are extensively manufactured. The valuation of personal property in 1870 was $12,367,611. Allegheny is the second county in importance in the state. Capital, Pittsburgh.