Mesolongi is the chief town of the Prefecture of Aitoloakarnania. The region known as Aetolia, of which Mesolongi is part, was inhabited in prehistoric times. In the time of Philip II, the Aetolians emerged as a strong political force, and in the third century BC they formed the Aetolian League, which was an important focus for resistance against the spreading power of Rome.
Mesolongi was particularly prosperous during the seventeenth and eighteenth centuries, developing into the commercial and maritime centre of Central Greece. During the Greek War of Independence, the townspeople won great fame for their bravery and heroism. Mesolongi had thrown itself into the struggle as soon as the War of Independence broke out, and it received valuable support from Lord Byron, who died in the town in 1824. Perhaps, though, the greatest acts of heroism in Mesolongi are those associated with the siege of the town by the Turks. There were two sieges, in 1822 and 1825; on the second occasion, the water and food ran out altogether, and on 12 April 1826 the townspeople decided to break out, although they knew that the numerical superiority of the Turks was such that not all of them would escape. Their decision to risk death rather than surrender made the Mesolongi breakout a symbol of the entire War of Independence. Today, there are many monuments in the town connected with the breakout: the Breakout Gate, monuments to the leaders of the Greeks and to the Philhellenes who fought by their side, and a Museum with manuscripts, painting, maps and documents. The heroism of the people of Mesolongi has also inspired painters and poets from all over the world/
Mesolongi is known for its lagoon; it and the similar lagoon at nearby Aitoliko are among the largest wetlands in Europe. From the point of view of tourist interest, the most fascinating features of the lagoon are the narrow strips of land which separate it from the open sea, and the lake-dwellings made of wood, reeds and water-resistant vegetation, standing on piles in the lake.