It spreads out in a natural basin, surrounded by mountains and is the remnant of a huge ancient Miocene lake that reached an area of 164 square kilometres and at a depth of 50 meters.

Sitting at an altitude of 630 metres, the lake covers an area of 28 square kilometres with a coastline that reaches 34 km.

Lake Orestiada is mainly refreshed by the waters that descend from Mount Vitsi through Xiropotamos on the eastern banks, but also by smaller streams, such as Aposkepos, Foudouklis, Istakos, Fotini, Metamorfosi, Toichi, Agios Athanasios and Vyssinia.

Orestiada is surrounded by wooded hills, wet meadows, reedbeds, lakeside forests, marshes and fields, habitats that support a rich birdlife.

It is a eutrophic lake, which is due to agricultural waste from crops and chronic pollution from the city's municipal sewage.

Dominant trees around the lake are sycamores with the vegetation complemented by elms, cranberries, blackberries and wild roses.