The 1944 Cornwall–Massena earthquake occurred on September 5 at 12:38:45 am EDT in Massena, New York. It registered 5.8 on the moment magnitude scale and had a maximum Mercalli intensity of VIII (Severe). This area is part of the Saint Lawrence River Valley and the seismically active zone known as the Saint Lawrence rift system. The earthquake is the largest known in New York's recorded history and was felt over great distances.