Megalopoli (Greek: Μεγαλόπολη) is a town in the southwestern part of the regional unit of Arcadia, southern Greece.

[1] Megalopoli is situated in a wide valley, surrounded by mountains: the Taygetus to the south, the Mainalo to the north, the Tsemperou to the southeast and the Lykaion to the west.

The area of Megalopolis features lignite deposits, which are prone to catching fire in summer and can smoulder and scorch the earth for weeks.

These have been conjectured in modern times to be those of Pleistocene fossil animals which are still often unearthed from the area today, such as those of the extinct straight-tusked elephant.

[citation needed] The city was founded through a synodical of twenty to forty neighbouring communities between 371 and 368 BC by the Arcadian League in an attempt to form a political counterweight to Sparta.

In 353 BC, when Thebes had her hands full with the so-called Sacred War, the Spartans made an attempt to reduce Megalopolis; but the Thebans sent assistance and the city was rescued.

In 317 BC at the start of the Second War of the Diadochi, Polyperchon, the new Regent of the Macedonian Empire, besieged Megalopolis which had sided with his enemy Cassander.

[4] The town was struck by the massive Arcadia earthquake of 5 April 1965, in which 17 inhabitants died and 80% of residences were demolished or rendered uninhabitable.