Classical Halos was situated in the backswamp east of New Halos, on an old beach ridge near the present shoreline. Demosthenes informs us about the location of the classical city. In 346 BC an Athenian legation travelled to Pella to meet Philip II, reaching Halos via Chalkis and Oreos while the city was besieged by a Macedonian army under Parmenion. The story by Demosthenes proves that the city was located close to the shore, because the legation was able to reach the city, even when it was under siege.

Classical Halos was excluded from the treaty between Philip II and the Athenians. The city was besieged, taken and razed to the ground in 346 by a Macedonian army BC under Parmenion in 346 BC. Its citizens were expelled and the territory was given to the city of Pharsalos, an ally of Philip II.

The site was already investigated in 1906 by the Dutch archaeologist Vollgraff. He excavated at the magoúla west of the place where the steamers from Athens to Almirós moored and found a fragment of a large building and black sherds. The survey of the Voulokalíva area in 1990 revealed amphora knobs, loomweights and pottery dating from the 4th century BC and Hellenistic times. Classical Halos was a small city with possibly 2,000 inhabitants.