ARACHTHUS(Ἄραχθος, Plb. 22.9; Ptol. 3.13; Liv. 43.22; Plin. Nat. 4.1; Ἄρατθος, Strab. pp. 325, 327; Ἀτατθός, Dicaearch. 42, p. 460, ed. Fuhr; Ἄραιθος, Lycophr. 409 ; Tzetz. ad loc.;Arethon, Liv. 38.3; respecting the orthography, see Kramer, ad Strab. p. 325 : Arta), a river of Epirus, rising in Mount Tymphe and the district Paroraea, and flowing southwards first through the mountains, and then through the plain of Ambracia into the Ambraciot gulf. The town of Ambracia was situated on its left or eastern bank, at the distance of 7 miles from the sea, in a direct line.
The Arachthus formed the boundary between Hellas proper and Epirus, whence Ambracia was reckoned the first town in Hellas. The country near the mouth of the river is full of marshes. The entrance to the present mouth of the Arta, which lies to the E. of the ancient mouth, is so obstructed by swamps and shoals as scarcely to be accessible even to boats; but on crossing this bar there are 16 or 17 feet of water, and rarely less than 10 in the channel, for a distance of 6 miles up the river. Three miles higher up the river altogether ceases to be navigable, not having more than 5 feet in the deepest part, and greatly obstructed by shoals. The course of the river is very tortuous; and the 9 miles up the river are only about 2 from the gulf in a direct line. At the entrance, its width is about 60 yards, but it soon becomes much narrower; and 9 miles up its width is not more than 20 yards. At Ambracia, however, its bed is about 200 yards across; but the stream in summer is divided by sand-banks into small rivulets, shallow, but rapid, running at least 4 miles an hour. Above the town, it appears comparatively diminutive, and 5 or 6 miles higher up, is lost among the hills. This is the present condition of the river, as described by Lieutenant Wolfe, who visited it in 1830. ( Journal of the Geographical Society, vol. 3. p. 81.)