Langeloth is a census-designated place in Smith Township, Washington County, Pennsylvania. Langeloth has been assigned the ZIP code 15054. As of the 2010 census, the population was 717 residents. Langeloth began as a coal mining company town. Langeloth Metallurgical Company, now a unit of Centerra Gold, is the town's largest employer. It was the birthplace of noted former college football coach Barry Alvarez.