St. John's Roman Catholic Church and cemetery is of State significance for its associations with the Catholic Parish of Campbelltown, the second oldest parish in Australia. It is associated with the pioneers of the early Australian Catholic church, especially Father John Therry who designed the building. Construction of the masonry building was commenced in 1825 but it was not completed until 1841. It is thought to be the oldest masonry Catholic Church building in Australia. It is associated with James Ruse and Matthew Healy whose graves are located in the cemetery. The original headstone of James Ruse has been removed and in possession of Campbelltown Airds Historical Society for safe keeping. A replica is on the grave.