The Corinth Canal
separates the Peloponnese from mainland Greece.
The Peloponnese is a peninsula that covers an area of some 21,549.6 square kilometres (8,320.3 sq mi) and constitutes the southernmost part of mainland Greece. While technically it may be considered an island since the construction of the Corinth Canal in 1893, like other peninsulas that have been separated from their mainland by man-made bodies of waters, it is rarely, if ever, referred to as an "island". It has two land connections with the rest of Greece, a natural one at the Isthmus of Corinth, and an artificial one by the Rio–Antirrio bridge (completed 2004).
The peninsula has a mountainous interior and deeply indented coasts. The Peloponnese possesses four south-pointing peninsulas, the Messenian, the Mani, the Cape Malea (also known as Epidaurus Limera), and the Argolid in the far northeast of the Peloponnese. Mount Taygetus in the south is the highest mountain in the Peloponnese, at 2,407 metres (7,897 ft). Οther important mountains include Cyllene in the northeast (2,376 metres (7,795 ft)), Aroania in the north (2,355 metres (7,726 ft)), Erymanthos (2,224 metres (7,297 ft)) and Panachaikon in the northwest (1,926 metres (6,319 ft)), Mainalon in the center (1,981 metres (6,499 ft)), and Parnon in the southeast (1,935 metres (6,348 ft)). The entire peninsula is earthquake prone and has been the site of many earthquakes in the past.
The longest river is the Alfeios in the west (110 km), followed by the Evrotas in the south (82 km), and also the Pineios, also in the west (70 km). Extensive lowlands are found only in the west, with the exception of the Evrotas valley in the south and in the Argolid in the northeast. The Peloponnese is home to numerous spectacular beaches, which are a major tourist draw.
Two groups of islands lie off the Peloponnesian coast: the Argo-Saronic Islands to the east, and the Ionian to the west. The island of Kythira, off the Epidaurus Limera peninsula to the south of the Peloponnese, is considered to be part of the Ionian Islands. The island of Elafonisos used to be part of the peninsula but was separated following the major quake of 365 AD.
Since antiquity, and continuing to the present day, the Peloponnese has been divided into seven major regions: Achaea (north), Corinthia (northeast), Argolis (east), Arcadia (center), Laconia (southeast), Messenia (southwest), and Elis (west). Each of these regions is headed by a city. The largest city is Patras (pop. 170,000) in Achaia, followed by Kalamata (pop. 55,000) in Messenia.