ACHELOUS (mod. Aspropotamo, “white river”), the largest river in Greece (130 m.). It rises in Mt. Pindus, and, dividing Aetolia from Acarnania, falls into the Ionian Sea. In the lower part of its course the river winds through fertile, marshy plains. Its water is charged with fine mud, which is deposited along its banks and at its mouth, where a number of small islands (Echinades) have been formed. It was formerly called Thoas, from its impetuosity; and its upper portion was called by some Inachus, the name Achelous being restricted to the shorter eastern branch. Achelous is coupled with Ocean by Homer (Il. xxi. 193) as chief of rivers, and the name is given to several other rivers in Greece. The name appears in cult and in mythology as that of the typical river-god; a familiar legend is that of his contest with Heracles for Deianira.