Hexamil, or Hexamiltum, a celebrated wall, built by the emperor Emanuel in 1413 over the isthmus of Corinth. It took its name from ἕξ, six, and μίλιον, which in the vulgar Greek signifies a mile, as being six miles long.

The design of the hexamilion was to defend Peloponnesus from the incursions of the barbarians. Amurath II. having raised the siege of Constantinople in the year 1424, demolished the hexamilion, though he had before concluded a peace with the Greek emperor. The Venetians restored it in the year 1463, by 30,000 workmen, employed for 15 days, and covered by an army commanded by Bertoldo d'Este general of the land forces, and Louis Loredano commander of the sea.—The infidels made several attempts upon it; but were repulsed, and obliged to retire from the neighbourhood thereof; but Bertoldo being killed at the siege of Corinth, which was attempted soon after, Bertino Calcinate, who took on him the command of the army, abandoned, upon the approach of the beglerbeg, both the siege and the defence of the wall which had cost them so dear; upon which it was finally demolished.