Karns City High School is located in Karns City, Pennsylvania. It is part of the Karns City Area School District. The school serves students residing in Butler County, Pennsylvania and Armstrong County, Pennsylvania. The boroughs of Chicora, Fairview, Karns City, Petrolia, and Bruin, as well as the townships of Parker, Fairview, Donegal, Perry, Sugar Creek, Brady's Bend, and Brady are within Karns City School District boundaries.