Mountains dominate the north, northeast, west and southeast, especially theAcarnanian Mountains. The longest and main river is theAcheloos, which ends as a delta in wetlands to the southwest on a rich fertile valley. The second longest isEvinos; others include theErmitsa, theInachos, and theMornos (on the border with Phocis). The regional unit excludes the islands lying to its west, since they belong to theKefalonia andIthaca regional units. There is one reservoir and a lake in its central part. The many mountains of the area span thePanaitoliko toward the northeast and theAcarnanian Mountains, theValtos and theMakrynoros mountains in the north, theNafpaktia Mountains in the southeast, theArakynthos andKravara in the south.
Lakes include theAmvrakia, theLysimachia,Ozeros, andTrichonida, and artificial lakes and reservoirs includeKastraki,Kremasta, the largest lake in Greece since its creation in 1970, andStratos. Two lagoons are found in the southern part of the regional unit: theMessolongi and theAitoliko. The lowest altitude in Greece is found in west Aetolia-Acarnania at about -10 meters from the sea level.[2]
Its climate ranges from hot and humid summers, with temperatures often surpassing 40 °C, to mild and short winters in the low-lying areas, with cool winters dominating in the mountain areas. At the highest elevations, summers are cool, and snow and cold weather dominate the winter months in the Panaitoliko.
Aetolia and Acarnania became a prefecture and merged to form Aetolia-Acarnania after theGreek War of Independence in the late-1820s; the prefecture includedEvrytania at the time, and it ranked second largest in Greece. Evrytania separated from the prefecture in 1948. In the 20th century, ferry services betweenRio and thePeloponnese began. and in the 1950s and the 1960s ferry services began to incorporate vehicles. FollowingWorld War II and theGreek Civil War a number of buildings needed to be repaired.
A drawbridge linking the island of Lefkada was built in the 1960s. The prefecture's first reservoir, created by theAcheloos Dam over theAcheloos, was under construction in 1967 and completed in the early 1970s, delivering water and hydropower to western part of Greece. Villages were relocated at the time. Two more dams were added, theStratos Hydroelectric Dam in the 1980s and another in the late 1980s.
The following years, GR-5 bypassed Messolonghi and Agrinion and GR-38 became connected with paved road with Eurytania and Phthiotida. In the late-1980s, the by-pass of Naupaktos began construction but after paving the road, the signs did not appear and until 1998, it was left unopened. In 1999, the road was re-repaired and finally opened to traffic. In 2000, the construction of the Rio-Antirio or theCharilaos Trikoupis Bridge connecting the Peloponnese began construction and was opened to traffic in August 2004. The superhighway, theIonia Odos (Ionian Motorway) which will run centrally bypassing communities began construction in 2001 at a part between Messolonghi and the curve, this section remains to be unpaved, the rest of the highway is in plan but the opening date is not yet set.
A railway formerly served the places fromKryoneri andAgrinio and served with the ferry withRio. In the 1980s, the service came to an end.
The regional unit Aetolia-Acarnania is subdivided into 7 municipalities. These are (number in parentheses corresponds to number in the infobox's map):[4]
As a part of the2011 Kallikratis government reform, the regional unit Aetolia-Acarnania was created out of the formerprefecture Aetolia-Acarnania (Greek:Νομός Αιτωλοακαρνανίας). The prefecture had the same territory as the present regional unit.[4] At the same time, the municipalities were reorganised, according to the table below.[5]