Butler is a city and the county seat of Butler County, Pennsylvania, United States. It is located 35 miles (56 km) north of Pittsburgh and is part of the Greater Pittsburgh region. As of the 2020 census, the city population was 13,502.

Richard Butler was an officer in the Continental Army during the American Revolutionary War who was later killed while he was fighting Native Americans in the United States in a battle that is known as St. Clair's Defeat.