The diocesan land area of 29, 857 square kilometers includes West Bengal's major urban centers – Kolkata, Kharagpur and Haldia port. The total population of 34,656,781 is a mix of ethnicities and religions.
Bengali is the official language of West Bengal, but English is the official language used by the archdiocese.
The first Christian settlements in Bengal appear at the end of the 16th century around the basilica in Bandel, which was buit in 1599 beside the Hooghly River. In 1834, at the petition of Calcutta Catholics, the Holy See erected the Vicariate of Bengal and entrusted it to the English Province of the Society of Jesus, and at the end of 1838 to the diocesan clergy.
On Feb. 17, 1845, the Holy See divided the Vicariate of Bengal into the Vicariates of Calcutta and Chittagong, the latter to be administered by its own Ordinary under the direction of the Apostolic Vicar of Calcutta. On Feb. 15, 1850, the two Vicariates of Calcutta and Chittagong were constituted as the independent Ecclesiastical units of West Bengal and East Bengal, respectively.
In 1856, at the request of Msgr. Oliffe, Apostolic Vicar of West Bengal, the Holy See entrusted the Vicariate to the Belgian Jesuits. The Vicariate was elevated to the Archdiocese of Calcutta in 1886.
The Communist Party of India (Marxist) ruled the state from 1977 until May 2011, when the Trinamool Congress defeated the world's longest-serving elected communist government.
Famous for Rabindrasangeet music, Baul (traditional country songs with accompaniment on a one-stringed wooden instrument), folk theatre.
The most well-known Catholic pilgrimage centres in the archdiocese are the Basilica of the Holy Rosary in Bandel and Mother Teresa's tomb in the Missionaries of Charity motherhouse in Kolkata.