Halos (, also appearing as ὁ Ἅλος or ἡ Ἅλος) or Halus, also Latinised as Alos and Alus, was a town and polis in the region of Achaea Phthiotis in ancient Thessaly, on the west side of the Pagasetic Gulf. It is located 10 km south from present-day Almyros. In Greek mythology Halos and Orchomenus are variously recorded as starting point of Phrixos' and Helle's flight to Colchis. The town is mentioned in Homer's Catalogue of Ships in the Iliad. According to Strabo, the town was situated near the sea, at the extremity of Mount Othrys, above the plain called Crocium, of which the part around Halos was called Athamantium, from Athamas, the reputed founder of Halus. Strabo also says that the river Amphrysus, on the banks of which Apollo is said to have fed the oxen of Admetus, flowed near the walls of Halus.