Arachthos river is the eighth longest river in Greece. Its length is 110 km. The start of the river is at Pindos mountains and it flows into Amvrakikos Gulf. It passes through a part of Ioannina and crosses Arta. Kalarrytikos, Metsovitikos and Zagoritikos tributaries connect with Arachthos.

A legend has it that three brothers lived in a little house on the peak of Peristeri mountain, in the heart of Pindos mountain range. Their names were serious Arachthos, beautiful Salampria (Pineios), and untamed Lefkos (Achelous). One night Salampria secretly left home to go down to the plain and meet one of the Gods of Olympus. However, she got disappointed when her date did not show up and fell in the Aegean sea.

When Lefkos realized that Salampria was missing, he rushed down the mountain without second thought. The dawn found Arachthos silent and sad because he had lost his brother and sister. He then began wandering through Epirus to find them. His journey lasted 110 km. starting from the peak of Pindos till Amvrakikos Gulf, near Arta. When he realized he had lost his siblings, he fell in the sea and drowned.

Almost all the bridges of the river are associated with myths. The most famous is the bridge of Arta. According to the myth, the bridge was being built in the morning but was collapsing at night. It only stayed in place when the master builder sacrificed his beautiful wife. This myth turned into a folk song which was sang in 333 different ways and travelled throughout Southeast Europe.

The river is ideal for water sports such as canoe and kayak.