Lake Prespa, Ancient tectonic lake at Macedonia-Albania-Greece border, North Macedonia

Lake Prespa is a pair of tectonic lakes, Great Prespa and Little Prespa, at 853 metres in the Balkans where North Macedonia, Albania and Greece meet. Great Prespa covers 259 km2, mostly in North Macedonia, and holds the tripoint; Little Prespa lies mainly in Greece. A 4 km isthmus with a road through Psarades separates them, and a short canal links the two on its western side.

In Classical times the lakes lay in ancient Lynkestis and were called Little and Great Brygeis. In the 10th century Tsar Samuel built the fortress and church of St. Achillius on Agios Achillios island in Little Prespa. The Prespa Agreement was signed at Psarades on 17 June 2018.

The name Prespa is attested from Byzantine times; in Classical antiquity the lakes were called Little and Great Brygeis. On Agios Achillios, an island in the Small Prespa Lake, Tsar Samuel built a fortress and the church of St. Achillius in the 10th century. The Prespa Agreement was signed on 17 June 2018 at Psarades by foreign ministers Nikola Dimitrov and Nikos Kotzias.

The lake is best reached through the town of Resen, which offers lodging and starting points for water activities. Visitors should note that the border location of three countries may affect access to certain areas.

Underground channels link this lake to the nearby Lake Ohrid, creating a natural filtration system through the karst mountains between the two water bodies. This hidden connection is invisible to most visitors but influences the water quality of both lakes.