Peirasia (Ancient Greek: Πειρασία) or Peiresia, was an ancient Greek polis (city-state), located in the tetrad of Thessaliotis in western Thessaly, close to the confluences of and Enipeus. In mythological sources, it is often connected with Asterium, the home of Asterion, one of the Argonauts. The site of Peirasia has recently been securely identified with the archaeological remains at in the region of Karditsa. Peirasia struck coins in the 4th century BC, depicting Athena Itonia on the obverse, and a horseman on the reverse, with the legend Peirasieōn.