In a land area of 8,293 square kilometers, the diocesan territory covers the entire union territory of Andaman Nicobar Islands which consists of nearly 350 islands scattered in Bay of Bengal.
Port Blair, a former British Penal settlement, named after Captain Blair of the East India Company, is the Capital of the Union Territory.
It is connected both by air and sea to the mainland (Chennai and Kolkata).
Port Blair is the biggest town in the diocese. Garachama and Bambooflat are other towns in the diocese.
Nearly 433,634 is the total population. The population is a cosmopolitan group of Bengalis, Punjabis, Tamilians and Malayalis.
Hindi, Tamil, Malayalam, Sadhri, Nicobarese, Urdu, Punjabi, Bengali, Telugu and English are the languages used in the diocesan territory.
The Andaman and Nicobar Mission was under the archdiocese of Rangoon - Burma. After India became independent in 1947, the Holy See handed over the whole area of Andaman and Nicobar to the archbishop of Ranchi. In 1965, at the request of the archbishop of Ranchi, the area was handed over by the Holy See to the Pilar Fathers, Goa. On June 22, 1984, Pope John Paul II elevated it into a diocese and appointed Father Alex Dias, S.F.X., once a priest here, as its first bishop.
The City is managed by corporation. The villages and small towns are administered by elected local bodies called panchayats and municipalities respectively.
The diocesan area is well connected in terms of transport infrastructure by sea and airways. The nearest airport is in Port Blair city.
The per capita income in the diocese territory is Rs 36,641 ($802) as of February 2011.
Government and private operators provide extensive telecommunication facilities in the diocesan area. The diocese is well connected by local cable TV networks.
Nearly 77.42 percent is the literacy rate in the diocesan territory.