Arachthos is a river in eastern Epirus in Greece that flows from the Pindus mountains and begins in the area southeast of Metsovo in the Ioannina Prefecture near the Trikala Prefecture and flows by numerous village including Elliniko. It enters the Arta Prefecture and into the Arachthos Dam which is about 20 km² and prevents flooding of the city as well as supplies water to the most of Epirus. Near the dam is the town of Peta southeast and within the river is the GR-30 (Arta – Karditsa) and flows into Arta’s historic landmark, the Bridge of Arta which is north of the modern day bridge of the Old GR-5. It is made up of stones. The river flows into a small plain and into an area that has grasslands and swamps and is surrounded by farms and finally empties into the Ambracian Gulf in Kommeno, south of Arta. The Arachthos Dam is to be found 2.6 km from Tzoumerka and is an artificial lake of great beauty.