Lake Mornos, Artificial reservoir in Dorida Municipality, Greece.

Lake Mornos is an artificial reservoir in the centre of Phocis, west of Lidoriki, filling the basin between the Giona and Vardousia mountains. Its dam, completed in 1979, is a 125-metre earth-fill structure with a clay core, the seventh tallest in Greece. At its mean level the water covers about 15.5 km², and the surface lies at 446 metres above sea level.

The reservoir was created between 1972 and 1979 when engineers dammed the river flowing through this mountain valley. The rising water submerged the settlement of Kallio, which existed here before the flooding occurred.

The reservoir takes its name from the Mornos river, which it dammed, and lies west of Lidoriki between Mount Giona and Mount Vardousia. Its water comes not only from the Mornos but also from tributaries such as the Kokkinopotamos, which rises in the Vardousia range, and from Lake Evinos through a connecting tunnel. The lake is part of the Natura 2000 network under code GR2450003.

Visitors can walk along the shore, fish, or take boats on the water in many areas around the lake. Wear sturdy footwear when exploring the banks, and be aware that water levels fluctuate seasonally depending on rainfall and water withdrawals.

During dry periods, water levels drop enough to reveal scattered remains of the old village of Kallio beneath the surface, including a stone bridge at a narrow passage called Steno. These occasional glimpses offer visitors a rare view into the submerged history of this valley.