ACHELOUS (mod. Aspropotamo, "white river"), the largest river in Greece ( i3om.). It rises in Mt. Pindus, and, dividing Aetolia from Acarnania, falls into the Ionian Sea. Its water is charged with fine mud, which is deposited along its banks in fer tile, marshy plains. At its mouth, a number of small islands (Echinades) have been enveloped in this deposit. It was formerly called Thoas, from its impetuosity, and its upper portion Inachus, the name Achelous being restricted to the shorter eastern branch. The name is given to several other rivers in Greece, and appears in cult and in mythology as that of the typical river-god.