The lake has a circular shape typical of crater lakes. Its surface area is 475,000 m² the altitude of its surface is 452 m and has a perimeter of 2,516 m.
The emissary which leaves Lake Mezzano is river Olpeta, that is an affluent to Fiora.
In the 1980s an archaeologic campaign brought back to light a number of historical and prehistorical findings. Many of those are now exhibited in the Museo della Preistoria e della Rocca Farnese in Valentano.