FARRELL, a borough of Mercer county, Pa., U.S.A., on the Shenango river, at the western boundary of the State, 6om. N.N.W. of Pittsburgh, and adjoining the city of Sharon, with which it forms virtually an industrial unit. It is served by the Erie, the Mercer Valley, the New York Central, the Pennsylvania, and the Pittsburgh and Lake Erie railways. The population was 15,586 in 1920, of whom 6,504 were foreign-born white; and was in 1930. It has important manufactures of steel, wire, tin plate,. sheet steel and iron, castings, boilers and coke. The borough was incorporated in 1901, and took the name of Farrell.