The creation of the lake "Trichonida" is the result of intense geological phenomena that took place 15-20 millions of years ago. The present lake is part of an older and larger lake that covered the whole valley of Agrinio in the prehistoric era.

According to tradition, inside the lake there used to be an ancient city that sunk. This city had three cones that gave -according to a theory- the lake its name (tri (three) - choni (cones)). According to another theory, which is also the most dominant, the name of the lake derives from the ancient city "Trichonio" situated by the lake, near the village "Gavalous".

The lake of Trichonida covers an area of 96,5 km, its perimeter is 51 km. and its depth is about 57 meters. To the east, the mountains spill into the shores of the lake, while the rest of the lake's shores are smooth, resembling sea-shores.  Around the lake there are five (5) extended municipalities (three former municipalities and 24 communities).

The volume of the water reaches about 142 million cubic meters. Its waters come from springs, mainly underground, and 15 large rivers that flow from the mountains of "Panaitolikos" and "Akarynthos". Part of its waters also come from the drainage of the region "Panaitolio-Kainourgio". The lake of Trichonida is connected with the lake of "Lysimachia" through a canal.

The lake of Trichonida provides water to the fields of "Lesinio", "Katochi", "Neochori" and "Mesologgi". The weather conditions during the past few years favored the upwelling of the lake's water levels by 1 meter and 20 cm. The water temperature varies according to season from 4° - 25° degree celcius.

The residents of the Municipalities situated by the river of Trichonida greatly benefit from its waters, as it provides water to the communities, farmers use it in their fields, and many residents engage in fishing activities. 

General Ecological Information

Trichonida is the natural habitat of 140 species of birds. 30 of these species are threatened by extinction and thus are protected by special regulations.  

The vegetation around the lake includes centuries-old plane trees (platanus), willow trees, eucalyptus, canes, citrus trees, bay trees and many more. The scents of the aromatic plants and flowers in springtime are lovely. Right over the lake, a bit further away from the village "Petrochori", there is a relatively large oak-tree forest.

In the region, there are rare flowers such as cyclamen, orchids and water lilies. The lake and the surrounding area is also a natural habitat for a variety of amphibians and reptiles, as well as for other animals, some of which are rare. For example, here lives the European otter (lutra lutra), also known as the Eurasian otter.

The lake is also home to a wide range of freshwater fish species, some of which are endemic and some rare, such as "gournara" (Tropidophoxinellus hellenicus), "tseroukla" (Scardinius acarnanicus), "trichovelonitsa" (cobitis trichonica), "glanidi" (silurus aristotelis), "nanogovios" (which is an endemic fish of Trichonida and its size is only 2cm long), "kyprini" (cyprinus carpio carpio), eels, ect. The lake is also habitat of various sponges, shells and marine molluscs. 

The phytoplankton composition of the lake includes 90 species, some of which are unique in the world. There are also 7 different categories of seaweed.

Kostis Palamas, our national poet, praised the beauties of Aitoloakarnania in his poems and he specifically referred to the lakes of Trichonida, Lysimachia and Acheloos. The traveler D. Vikelas also referred to the lake and its exceptional beauty in his writings in 1885.

Panaitoliko is the last mountain of Roumeli before reaching the valley of Agrinio, rising over the lake of Trichonida. Its steep slopes are filled with fir trees until an altitude of 1,400 m. On the lower level there are cedar trees and shrubs. The mountain of Panaitoliko is home of various birds of prey, such as the Golden Eagle (Aquila chrysaetos), the Common Buzzard (Buteo Buteo), the Short-toed Eagle (Circaetus gallicus) and a plethora of Woodpeckers (Picus viridis) and other small birds.

Across the mountain of Panaitolikos stands the legendary mountain of Arakynthos, a place of great ecological value. Its vegetation mainly consists of the Mediterranean "makia" bushes, various shrubs, conifer trees and oak trees. By its river banks there are plane trees, part of a wider forest land. The region of "Kleisoura" is home for a number of prey birds, such as the Golden Eagle, the Peregrine Falcon (Falco peregrinus) and many more. Finally, during the winter many rare birds find refuge in the region, such as the Black Vulture (Aegypius monachus), the Eastern Imperial Eagle (Aquila heliaca) and the Greater Spotted Eagle (Aquila clanga).