The Acheloos (Greek: Αχελώος), also Achelous, is a river in western Greece. It formed the boundary between Acarnania and Aetolia of antiquity. It empties into the Ionian Sea. In ancient times its spirit was venerated as the river god Achelous.

The river today begins in the prefecture of Trikala in the Pindus range near the Lakmon mountains at the elevation of about 2,295 m and has its first tributary, the Aspropotamos, meaning the white river. It is also one of the longest rivers in Greece. The river flows with the boundary of the Arta prefecture which is also the boundary with Epirus. It later flows with the boundary of Karditsa in the east and later flows with the prefecture of Aitolia-Acarnania to the west and a few kilometres later with Eurytania in the east. The river runs into the reservoir in which used mark the river and ended the flow with the boundary. It still form the tributary with the Agraphioti river which has a lot of tributaries and starts in the Agrafa (ancient: Agrapha) ranges Afterwards and the Megdova river further east covering half of the Eurytanian basin in the west and the northern part, the Megdova begins in Karditsa and flows into a dam near the border with Eurytania. It flows southward to the present-day dam, the river is west of the Panaitoliko ranges and entirely into Aitolia-Acarnania and runs about 10 to 15 km downstream another dam. It later runs west of Agrinio and into the swamplands which is surrounded with forests and a 2-km long bridge of GR-5/E55 (Ioannina - Antirio) and flows witha tributary to two large lagoons in the east, it later flows into the Aitoliko Lagoon and in the middle of Aitoliko. The river empties into the Ionian Sea and partly in the Gulf of Patras via the Messolongi Lagoon west of Messolongi. The river has some canyons.

The previous name was Thoas. It is rarely known as Thestios and Axenos.

Acheloos River in mythology

Main article Achelous.

History

In the 1960s, the dam project in the Aitoloacarnania-Evrytania boundary was under construction. The area are not forested. The dam was under construction and the type is a concrete dam. It took years to complete and the flooding of the portion of the western part of the prefecture of Eurytania began. The dam includes a power station with transformer lines in the east. The dam powers electritity for the western part of Greece and the central part. It caused some soil erosion in some flooded valleys. Another dam which is named the Katsiki Dam is downstream. The arch bridges includes the Karafilio, the Ardanovo

Places

In order from upstream to downstream:

• Milea
  
• Agia Paraskevi
  
• GR-30
  
• east of Gardiki
  
• Polyneri
  
• Agrinio
  
• Fragouleika
  
• Aitoliko
  
• west of Messolonghi