In a land area of 38,700 square kilometers, the diocesan territory covers The diocese covers the civil districts of Darrang, Udalguri, Sonitpur, Lakhimpur and Dhemaji on the North bank of the Brahmaputra; Rupahihat, Kaliabor and Samuguri Subdivisions of Nagoan District on the Southern Bank of Brahmaputra.
Tezpur is the biggest town in the diocese.
In Tezpur Diocese, the population is 7,139,000 at end of 2009. (The population of the whole country is 1.2 billion). The major ethnic communities that reside in the diocesan area are Assamese, Mundas, Kharias, Oraons, Santals, Orias, Lohars, Boros, Garos, Rabhas, Deoris, Rajbongshis, Misings, Tiwas, Karbis, Nishis, and Apatanis.
English, Assamese, Hindi, Sadri, Mundari, Oraon, Kharia, Santali, Boro, Garo, Rabha and other local dialects are the languages used in the diocesan area.
On May 10, 1964, Pope Paul VI raised Tezpur to an Episcopal See, and nominated Orestes Marengo SDB DD, Bishop of Dibrugarh, as the Administrator of the newly erected Diocese of Tezpur. He was installed at Tezpur and took charge of the Diocese on Aug. 23, 1964. By his pastoral care, Bishop Marengo was able to consolidate the many new Christian communities and to bring about the over all development of the Diocese. He resigned in 1969. Father Joseph Mittathany was nominated the second Bishop of the Diocese on June 26, 1969, and he was ordained Bishop and installed on Sept. 27, 1969.
Bhutan, the independent kingdom in the Himalayas, formed part of the Diocese till 1976. It was separated and attached to the Diocese of Darjeeling by the Decree "Quo Facilius" (Jan 20, 1975).
John Paul II erected the Diocese of Imphal, Manipur on April, 2, 1980 and transferred Bishop Joseph Mittathany from Tezpur to Imphal as its first ordinary. The See being vacant, Father Mathew Kottaram was elected the Vicar Capitular. Bishop Robert Kerketta SDB DD, who had been Bishop of Dibrugarh from 1970, was transferred to Tezpur, and took charge of the Diocese on Jan. 31, 1981.
The Diocese of Guwahati was erected by the Apostolic Decree "Opitulante Quidem Domino" (30, March 1992). 15 Centres of the then Diocese of Tezpur in the Civil Districts of Kokrajhar, Dhubri, Barpeta, Nalbari, Kamrup, Morigaon and part of the District of Nagaon were taken to form part of the new Diocese. The Diocese of Guwahati was inaugurated on Aug. 16, 1992. Reorganization of the Ecclesiastical Province of Shillong-Guwahati took place on Aug. 1, 1994 and it provided for the creation of 3 Provinces in the region: Guwahati, Shillong and Imphal. Tezpur became a suffragan of Guwahati along with Dibrugarh and Diphu.
On Dec. 7, 2005 the Holy See announced yet another bifurcation of Tezpur and the creation of the Diocese of Itanagar, Arunachal Pradesh, with Bishop John Thomas Kattrukudiyil (of Diphu Diocese) as it first ordinary. The Erection of the Diocese and Installation of Bishop John Thomas took place on March 12, 2006. The Diocese of Tezpur today comprises the Civil Districts of Darrang, Udalguri, Sonitpur, Lakhimpur and Dhemaji on the North bank of the Brahmaputra; Rupahihat, Kaliabor and Samuguri Subdivisions of Nagoan District on the Southern Bank of Brahmaputra. Bishop Robert Kerketta after shepherding the diocese of Tezpur as its Bishop for a long glorious period of 27 years retired on Dec. 3, 2007 and is succeeded by Bishop Michael Akasius Toppo as its new ordinary.
The big towns are 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 roads. The nearest airport is in Guwahati city which is 185 kilometers from Tezpur.
Rupees 14,950 (about USD328 as of Jan. 2010) is the per capita income in the diocesan territory. Agriculture and Horticulture are the main sources of income. The territory also has Tea Industries, Textile Industry, Jute Mills.
Government and private operators provide extensive telecommunication facilities in the diocesan area. The diocese is well connected by local cable TV networks.
Approximately 70 per cent is the literacy rate in the diocesan territory.