Lousios is a Peloponnesian river, a tributary of Alpheus, with a length of approximately 23 km. According to tradition, got its name because in these waters nymphs Neda, Agno and Theisoa bathed the newborn Zeus.
Its sources are located in the church of Agia Paraskevi, near the village Kaloneri and southern in the ancient Theisoa. Lousios after passing Dimitsana, where there is the country Water Power Museum, trespasses a spectacular canyon of 15 kilometers length and 2 km width, before reaching the Alpheus, near Karytaina.
On both sides of the canyon there are two historic monasteries, the Monastery of the Baptist and the Philosopher’s Monastery.
The canyon was designated, in 1997, as an important archaeological site and it is protected by the Ministry of Culture.
On the west side of the canyon passes the 32 national trail (offshoot of the European path E4 GR), which starts at Vytina and ends in Gytheio. Lucius is suitable for alternative tourism (hiking, canoeing and rafting).