This island forms the Sagar CD Block in Kakdwip subdivision of South 24 Parganas district in the Indian State of West Bengal.

Every year on the day of Makar Sankranti (14 January), hundreds of thousands of Hindus gather to take a holy dip at the confluence of river Ganges and Bay of Bengal and offer prayers (puja) in the Kapil Muni Temple.

Later having compassion for the King Sagar's sons, Kapil Muni acceded to the prayers of King Sagar's descendants, agreeing to the restoration of the sons, if Parvati in the form of the river goddess Ganga would descend to Earth to perform the Last Ritual (Hindus also called as"Tarpan") of mixing the ashes with holy water (niravapanjali).

But later they i.e. the Gayen family's majority members embraced Islam but remained close to Kapil Muni and Jagadhatri Puja as they were then the Zamindars during the British Rule.

[6] The Gangasagar fair and pilgrimage is held annually on Sagar Island's southern tip, where the Ganges enters the Bay of Bengal.

[8] The Gangasagar pilgrimage and fair is the second largest congregation of mankind after the triennial ritual bathing of Kumbha Mela.

[9] In 2007, about 300,000 pilgrims took the holy dip where the Hooghly meets the Bay of Bengal on the occasion of Makar Sankranti.