 Northumberland County comprises the Sunbury, PA Micropolitan Statistical Area, which is also included in the Bloomsburg-Berwick-Sunbury, PA Combined Statistical Area.Among its famous residents, Joseph Priestley, the Enlightenment chemist and theologian, left England in 1796 due to religious persecution and settled on the Susquehanna River.His former house (originally purchased by chemists from Pennsylvania State University after a colloquium that founded the American Chemical Society) is a historical museum.