Saint Mary's Church was part of a parish organized in 1847 at Sartwell in the "Irish Settlement," originally formed from 1842 to 1860. A log church was built in 1848, and the present church was completed in 1871. Its resident pastor long served Roman Catholics throughout McKean and Potter counties, and it was the mother church of congregations at Port Alleghany, Bradford, Smethport, Eldred, Duke Center, and Costello. It later became a mission of Saint Raphael's at Eldred.