Venakgo, a N. W. county of Pennsylvania, drained by the Alleghany river, French creek or Venango river, and Oil, Sugar, and Sandy creeks; area, 850 sq. m.; pop. in 1870, 47,925. A large part of the county is traversed by spurs of the Alleghany mountains. The soil along the streams is fertile. Iron ore and bituminous coal are very abundant, and there are traces of silver mines. Lumber and oil are exported largely. This county forms the centre of the great oil basin of Pennsylvania, and there are hundreds of oil wells in the valleys. (See Petroleum.) It is traversed by the Oil Creek and Alleghany River, the Alleghany Valley, the Pithole Valley, and the Franklin divisions of the Lake Shore and Michigan Southern, and of the Atlantic and Great Western railroads. The chief productions in 1870 were 72,158 bushels of wheat, 28,610 of rye, 216,753 of Indian corn, 335,899 of oats, 63,267 of buckwheat, 75,355 of potatoes, 268,405 lbs. of butter, 92,355 of wool, and 27,879 tons of hay. There were 5,113 horses, 6,963 milch cows, 7,412 other cattle, 32,764 sheep, and 10,379 swine; 6 manufactories of boots and shoes, 16 of carriages and wagons, 25 of machinery, 24 of refined petroleum, 10 flour mills, 9 saw mills, and 5 woollen mills.

Capital, Franklin.