Langeloth is a census-designated place in Smith Township, Washington County, Pennsylvania, United States. 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 Thompson Creek Metals, is the town's largest employer. It is also the birthplace of noted former college football coach Barry Alvarez.