Altus or Altos ( ; ) was a fortress town in Mygdonia near Therma (later Thessalonica). The town is mentioned by Stephanus of Byzantium and Theagenes of Macedon. Its site is unlocated. References John Cramer, A Geographic and Historical Description of Ancient Greece (Clarendon Press, 1828), p. 238. Populated places in ancient Macedonia Former populated places in Greece Geography of ancient Mygdonia Lost ancient cities and towns