In a land area of 6,400 square kilometers, the Tuticorin diocesan territory covers the whole Tuticorin civil district and parts of Tirunelveli civil District. Majority of the population of 2,702,123 are Tamils, and the major language in the area is Tamil.
According to the directorate of economics and statistics, 2001-2002, the per capita income in the diocese territory is 22,781 rupees (about US$506). The major industries, trade and agriculture is fishing, paddy, ragi, salt, petrochemical, palm products. Tuticorin also has a major sea port. According to the census of 2001, the literacy rate in Tuticorin is 81.52 percent.
1535-37 - People from 30 villages in Tuticorin Coast receive baptism
1538 - First church was built in Tuticorin dedicated to St. Peter, the Apostle
1542 - St. Francis Xavier arrives in Tuticorin in the month of October
1548 - St. Francis Xavier convenes the first priests meeting in Manapad, a village some 40 km from Tuticorin
1555 - The statue of Our lady of Snow arrives in Tuticorin on June 6 by a ship named Santelena sent by Augustinian sisters in Manila on the request of St. Francis Xavier
1558 - The church of Our Lady of Snow was built. The first seminary was inaugurated.
1578 - First printing press in Tamil Nadu was established in Punnaikaiyal village.
1658 - Dutch capture Tuticorin from Portuguese; Catholics are harassed for their faith. Catholic Churches in Coromandel Coast destroyed.
1680 - St. John de Britto, who was martyred in Oriyur, built a church in Vadankulam dedicated to The Holy Family.
1690 - A large number of people in Vadakankulam receive baptism
1711 - A new church of Our Lady of Snow is completed.
1785 - Vatican gives permission to French Missionaries to work in the diocese. However, the powers of Portuguese Padroado bishops continue. The dual administration of the diocese begins.
1849 - Cathedral of Sacred Heart of Jesus is blessed.
1894 - On November 25, Lawrence Xavier of Manapad becomes the first Indian priest.
1923 - On June 12, Pope Pius XI separates Tuticorin from Tiruchi diocese and creates the first Indian-administered Latin-rite diocese.
1923 - On September 23, Bishop Gabriel Tiburtius Roche was installed as the first Indian bishop of the Latin rite dioceses.
1930 - Parishes under the administration of Portuguese Padroado bishops in Mylapore diocese join Tuticorin diocese. The dual administration comes to an end.
1948 - The diocese celebrates its silver Jubilee.
1955 - Bishop Tiburitius Roche dies and is buried in the cathedral.
1973 - The diocese celebrates its Golden Jubilee.
1982 - Pope John Paul II raises the church of our Lady of Snow to a status of a major Basilica.
1998 - The diocese celebrates platinum jubilee
2001-03 - The diocese conducts the Diocesan Synod.