BUTLER, a city of Pennsylvania, U.S.A., on Cohoquenessing creek, about 3om. N. of Pittsburgh; the county seat of Butler county. It is served by the Baltimore and Ohio, the Pennsyl vania, the Buffalo, Rochester and Pittsburgh, and the Bessemer and Lake Erie railways. The population in 192o was 23,778, and was 23,568 in 1930 by the Federal census. It is built on a hill about i,oioft. above sea-level and commands extensive views of the valley. Oil, natural gas, limestone, coal, and iron abound in the vicinity, and the city has important manufactures, including plate-glass, steel cars, car wheels, motor tyres, metal pipe, oil well machinery, and petroleum products. The total factory out put in 1925 was valued at $22,396,963. When Butler county was formed in 1802, this site was selected for the county seat, and in 1803 the borough was laid out and incorporated. A city charter was secured in 1917. County and city were named after General Richard Butler, a Revolutionary soldier and friend of Washington.