Lousios is a river in the Peloponnese, a tributary of Alfios, with length of about 23 kilometres. According to the tradition, the river was given this name because the newborn Zeus was bathed (“louzo” means bathing in Greek) in its waters by the nymphs Neda, Agno and Theisoa. Its springs are in the church of Agia Paraskevi, near the village of Kaloneri and further south in the location of ancient Theisoa.

Lousios, after passing west of Dimitsana, where there is the Open-Air Museum of Water Power, crosses an impressive gorge 15km long and about 2km wide, before ending up in Alfios, near Karytaina. On each side of the gorge there are two historic monasteries, the Monastery of Filosofos and the Monastery of Prodromos. The gorge was characterized in 1997 a single archaeological site and is protected by the Ministry of Culture.

On the western side of the gorge passes the national trail 32, which originates from Vytina and ends in Gythio. Lousios is ideal for alternative tourism activities (e.g., hiking, canoeing, kayaking, and rafting).

For out-of-town activities, surrounded by nature, it is sure to be an excellent choice.