Butler is a city and the county seat of Butler County, Pennsylvania, United States. It is 35 miles north of Pittsburgh and part of the Greater Pittsburgh region. As of the 2020 census, the population was 13,502. Butler is named after Major General Richard Butler, who died in the Battle of the Wabash in 1791. It was first settled in 1803 by John and Samuel Cunningham and incorporated as a borough in 1817 before becoming a city in 1918.