[3] The Great Prespa Lake (Macedonian: Преспанско Езеро, Prespansko Ezero, Albanian: Liqeni i Prespës së Madhe, Greek: Μεγάλη Πρέσπα, Megáli Préspa) has the total surface of 259 km2 (100.00 sq mi).

The two lakes are separated by a 4-kilometre-long (2.5 mi) and 500-metre-wide (550 yd) isthmus on the Greek territory, carrying an embankment with a road connecting the village of Psarades.

In the 10th century, the Tsar Samuel built the fortress and church of St. Achillius on an island called Agios Achillios in the Small Prespa Lake, on the Greek side of the border.

The other island Mal Grad ("Small Town", in Albania) is the site of a ruined 14th century monastery dedicated to St. Peter.

[6] For many years, the Greek part of the Prespa Lakes region was an underpopulated, military sensitive area which required special permission for outsiders to visit.

It saw fierce fighting during the Greek Civil War and much of the local population subsequently emigrated to escape endemic poverty and political strife.