In the early period of Sikhism, the word Dharamsala was used to refer to a Sikh place of worship and service. Later, the name was replaced by Gurdwara, which means the doorways to the Guru, or the door that leads to the Guru, the spiritual teacher. However, in Sikhism the Guru is not any particular person, it is the Guru Granth Sahib, the book of Sikh scriptures. Although it is believed that God is present everywhere, the Sikhs have neither any idol, nor any sacrament in the Gurdwaras. However, the essential part of a Gurdwara is the presiding presence of the Holy Scripture, the Guru Granth Sahib, which is also referred to as Satguru. The presence of Guru Granth Sahib gives the Gurdwaras its religious status. A Gurdwara is thus a symbol of serenity, a place of assembly and worship for the Sikhs, which is open to all, irrespective of any other faith. Each Gurdwara has a Darbar Sahib where the Holy Scripture, Guru Granth Sahib is placed on an elevated throne, called Takhat, under a canopy, while the Raagis sing Raagas, recite and explain the verses from the Guru Granth Sahib, in the presence of the congregation, called the Sadh Sangat. A Gurdwara also includes a Langar hall, where anybody can have free vegetarian food served by the volunteers. Some of the Gurdwaras also provides medical facility and contain a library, nursery, classroom, meeting rooms, playground, even a gift shop.

Located on 172 Mahatma Gandhi Road (erstwhile Harrison Road), Gurdwara Bara Sangat is regarded as the most important historical Gurdwara in the city of Calcutta as it was believed to be visited by Guru Nanak, the founder of Sikhism and the first of the ten Sikh Gurus, and Guru Tegh Bahadur, the ninth of the ten Gurus who founded the Sikh religion and the head of the followers of Sikhism from 1665 until his beheading in 1675.

It is said that on his journey from Dhaka to Punjab, Guru Nanak arrived at this place on 2nd January 1510, when the locals were suffering miserably due to the onset of an epidemic. During that time, he chanted the Gurbani Shabad, ‘Chanchal chit na pave pare’ for their relief, and stayed for 12 days. In another version, Guru Nanak visited the place in 1508, on his journey to Puri, to meet the famous spiritual leader Shree Chaitanya Mahaprabhu. Moreover, it is also said that Guru Tegh Bahadur, during his return journey from Assam, also arrived here in April 1668. During his stay, he recited Gurbani Shabad 'Har ki gat nah koi jaane', and advised to establish Guru ki Sangat to continue religious programmes and hold congregations regularly, along with 24 hrs Guru ka langar. Thus, as the Gurdwara Bara Sangat in Calcutta is blessed by both the Gurus and made sacred by their visit, it has special historic importance in the city.

In those early days, the site of the Gurdwara was almost a forest and marshy area. It is estimated, probably the original shrine was in a part of the estate of Raja Hazuri Chand, who built the original shrine and maintained it until his death. After his demise, his daughters Shyam Kaur and Lila Kaur continued to look after it. Over time, the management of the shrine fell into incompetent hands until a management committee was formed in 1852 AD. Although the condition of the Gurdwara improved temporarily, in the beginning of the 20th century mismanagement again crept in. Between 1910 and 1922, the building and the other property of the Gurdwara were mortgaged four times, and each time for a higher amount.

In April 1920, a new management committee, comprising 16 members, was formed, and in December 1920, the newly formed committee decided to hand over the Gurdwara to the newly formed Shiromani Gurdwara Parbandhak Committee (SGPC) at Amritsar. However, the situation became complicated on 11th December 1929, when the mortgagee went to court, which decided that unless the dues were cleared within six months, the Gurdwara would be auctioned. Finally, the unwanted situation was avoided as a result of mutual understanding between the parties, and the debt was cleared by April 1937. Since then, the Gurdwara has been functioning well.

Situated in the heart of a crowded and busy business centre of Calcutta, the Gurdwara Bara Sikh Sangat hosts social gatherings and provides accommodation for the guests.