The 1737 Calcutta cyclone, also known as the Hooghly River cyclone of 1737 and the Great Bengal cyclone of 1737, was a tropical cyclone of South Bengal regarded as one of India's worst natural disasters. It hit the coast near Kolkata on the morning of 11 October 1737 and presumably killed over 300,000 people inland and sea, and caused widespread catastrophic damage. The cyclone hit land over the Ganges River Delta, just southwest of Calcutta. Most deaths resulted from storm the surge and happened on the sea: many ships sank in the Bay of Bengal and an unknown number of livestock and wild animals were killed from the effects of the cyclone. The damage was described as "extensive" but numerical statistics are unknown.