Riolos , is a village and a community in the municipal unit of
Larissos,
Achaea,
Greece. It is located on the northwestern edge of the
Movri hills, 4 km north of
Mataragka, 3 km southwest of
Krinos, 6 km southeast of
Lappas and 32 km southwest of
Patras. In 2001 Riolos had a population of 801 for the village and 810 for the community, which includes the small village Mazaiika. The river
Larissos flows southwest of the village. During the
Greek War of Independence a battle took place in Riolos in which the Greeks, led by
Thallis Theodoridis the Elder, were victorious.