Linesville is a borough in Crawford County, Pennsylvania, United States. The population was 961 at the 2020 census, down from 987 at the 2019 census. The town derives its name from its founders, who included William Line, who migrated from Carlisle, Pennsylvania, circa the early 1820s, and his relative, Amos Line, who was the town's surveyor and main proprietor. Amos Line "penetrated the western Pennsylvania wilderness as a member of the Pennsylvania Population Company in the early 1800s."