Lake Koronia (Greek: Λίμνη Κορώνεια) is a lake in the heart of the prefecture of Thessaloniki in the basin of Mygdonia in the Lagada province, Greece. The lake is also known as Agios Vasilios from an homynous village or Lake Lagada. It is located a few kilometres east of downtown Thessaloniki and in the north side is the Via Egnatia and the south is the old highway. The municipalities with shores on the lake are Koroneia, Lagadas, and Egnatia.
A million years ago, Lake Koronia along with Lake Volvi and all of the Mygdonian basin was a large lake. From that time, the extension of the lake is shrinking and almost disappearing into a plain and from the distance from neighboring Lake Volvi is getting larger. In the 1950s, Koroneia was one of the lakes in Greece with the most production of fishing. In the 1970s, the size was 450 km² and had the depth of about 5 metres. In the beginning of the 2000s, the lake was 100 km² and the depth was about 0.5 to 1 metre. In the summer of 2002, the lake was very dry.