Crestonaean

Crestonaean, plural Crestonaeans, were probably a gallic tribe and region directly north of the modern city of Thessalonica.

We know that the river Echidorus (Ἐχείδωρος; Ἐχέδωρος), Cheidorus later named the Galliko, rose in their territory and emptied itself into a lagoon near the mouth of the Axios/Axius, which empties into the Thermaic Gulf of the Aegean Sea a little to the west of Thessalonica.

We know that Xerxes marched his army from the north of Therma through Crestonaea to meet his navy anchored there prior to the Battle of Marathon.