Onchestus or Onchestos (Ancient Greek: Ὀγχηστός), was a river of ancient Thessaly, flowing near Scotussa, through the battlefield of Cynoscephalae into Lake Boebeis.[1][2][3] It is perhaps the same river as the Onochonus or Onochonos (Ὀνόχωνος), whose waters were exhausted by the army of Xerxes I during the Persian invasion of Greece.[4][5] It is true that Herodotus describes this river as flowing into the Peneius; but in this he was probably mistaken, as its course must have been into Lake Boebeis.
References
This article incorporates text from a publication now in the public domain: Smith, William, ed. (1854–1857). "Onchestus". Dictionary of Greek and Roman Geography. London: John Murray.