Diamond Harbour is a town and a municipality of the South 24 Parganas district in the Indian state of West Bengal. It is situated on the eastern banks of the Hooghly River. It is the headquarters of the Diamond Harbour subdivision.

South 24 Parganas (Pron: pɔrɡɔnɔs; abbr. 24 PGS (S)), or sometimes South Twenty Four Parganas and Dakshin 24 Parganas, is a district in the Indian state of West Bengal, headquartered in Alipore. It is the largest district of West Bengal by area and second largest by population. It is the sixth most populous district in India (out of 640). On one side of the district there is the urban fringe of Kolkata, and on the other the remote riverine villages in the Sundarbans.