The celebration commemorates the inauguration of the first Brahmo Samaj by Ram Mohan Roy on 23 January 1830, which was on 11 Magh according to the Bengali calendar in that year.
It is celebrated by divine service or prayer, offered by the acharya or minister, interspersed with devotional hymns popularly known as Brahmasangeet.
The other Samajes in Bengal like Harinavi, Konnagar, Baniban, Nimta, Puddopukur also join in the festivities.
A special divine service is held on 11 Magh at Jorasanko Thakur Bari - the seat of the Tagore's in Kolkata where ministers from the three main Samajes join together in performing the Maghotsav.
The songs are sung by the music group Baitanik - founded by late Soumendranath Tagore.