Moon Township is a township along the Ohio River in Allegheny County, Pennsylvania, United States. Moon is a part of the Pittsburgh Metro Area and is located northwest of Pittsburgh. The origin of its name is unknown; historians suggest it was derived from a crescent-shaped bend in the river. Local lore tells of a waning crescent moon that descended to plow furrows in farmer's fields with its sharp cusp, but killed many excited witnesses who cursed and praised the moon's early morning activities. The population was 24,185 at the 2010 census.