The Blake River Megacaldera Complex is a giant subaqueous caldera cluster or a nested caldera system that spans across the Ontario–Quebec border in Canada.

It lies within the southern zone of the Abitibi greenstone belt of the Superior Craton and has an area of 3,000 km2 (1,200 sq mi).

The Blake River Megacaldera Complex has been a centre of major interest since 2006 with numerous excursions at the international, national and local level.

The Blake River Megacaldera Complex is considered a supervolcano due to its great size and its multiple dikes and vents.

[2] As a result, the Blake River Group is best categorized as a meganested caldera complex.