Thamarassery is situated on the south west coast of India. In a land area of 5,893 square kilometers, the diocesan territory is bounded on the north by Kannur district, on the east by Wayanad, on the south by Malappuram and on the west by the Arabian Sea. The patroness of this eparchy is St. Alphonsa.
In 2017, the total population of the diocesan territory is 7,137,346. Thamarassery has been a multi-ethnic and multi- religious town. Hindus forms the largest community followed by Muslims and Christians.
Malayalam and English are in use in the territory.
Pope John Paul II erected the diocese of Thamarassery on April 28, 1986, by bifurcating the diocese of Tellicherry. The eparchy of Thamarassery consists of the two revenue districts of Calicut and Malappuram.
The Catholics of this diocese are the migrants from the central part of Kerala.
Bishop Sebastian Mankuzhikary, then auxiliary bishop of Ernakulam, was appointed first bishop of Thamarassery on the same day. The diocese was formally inaugurated and the bishop took charge on the feast of St. Thomas the Apostle of India, July 3, 1986, at the Sacred Heart Church, Thiruvampady.
Bishop Sebastian Mankuzhikary died on June 11,1994. Bishop Jacob Thoomkuzhy from Mananthavady was transferred to Thamarassery and he took charge on July 28, 1995. When he was made the archbishop of Trichur, Bishop Paul Chittilapilly from Kalyan diocese took charge of the diocese on Feb. 13, 1997.
Thamarassery belongs to Kozhikode district. The administration of Thamarassery is carried out by Thamarassery panchayath.
The territory is well connected by roads. The train service is limited to major towns. Calicut Airport is nearly 70 kilometers from the diocesan headquarters.
The economy of Thamarassery diocese is mainly based on agriculture. Rubber and coconut are the main cultivations. Major industries include timber industry and tile-making. A huge portion of its male population is employed in gulf countries, and the money they send home forms an important part in the local economy.
The level of telecommunications infrastructure is high. Almost everyone has a mobile phone. Most of the homes have television, telephone and internet. In rural areas access to internet is limited.
There are no television broadcasting stations in the territory but there are three radio stations. One is owned by the government. The other two are private FM stations having started broadcasting recently. Thamarassery diocese is the home of the first Catholic television channel in India-- Shalom Television.
Thamarassery known as the gateway of Wayanad district, is a small picturesque town in Kozhikode-Wayanad Road. Thamarassery is beautiful place blessed with greenery, small streams and hills. Thamarassery spreads across 56 square kilometers.