Farrell is a city in Mercer County, Pennsylvania, United States. The population was 6,050 at the 2000 census. It is part of the Youngstown–Warren–Boardman, OH-PA Metropolitan Statistical Area.
Once dubbed "The Magic City," Farrell sprung up practically overnight when a steel mill was constructed in 1901 on a plain bordering the Shenango River in what was then part of Hickory Township (now Hermitage).
The community was incorporated as the Borough of South Sharon in 1916; its population peaked at over 15,000 in 1920 and its status was elevated to a third-class city in 1932. At that time the residents of the new city elected to take the name of Farrell, after industrialist James A. Farrell.