The diocesan territory stretches over 28,490 square kilometers and covers civil districts of Coimbatore and parts of civil districts of Erode and Karur in the state of Tamil Nadu, and civil district of Palakad in the neighboring Kerala state. Coimbatore is the biggest city in the diocese with more than 1 million people. Erode and Palakad are other important towns in the diocese.
The population was 7,419,686 at the end of 2016.
Kannada, Malayalam, Tamil and Telegu are the languages spoken in the diocese.
Christianity took root in Coimbatore in the early 1650’s. A small chapel was built and named after Saint Francis Xavier. Jesuit priest Father Garrie, who was living Karumathampatty, met the spiritual needs of Christians in Coimbatore.
From 1656-1773, the Jesuits did mission work here, but later, due to the suppression of the Jesuit order by the pope, Coimbatore was given to the care of the French MEP missionaries in 1775.
On April 3, 1845, Karumathampatty became the headquarters of Coimbatore diocese. Coimbatore, which had formerly been part of Pondicherry archdiocese, was removed from the archdiocese on Oct. 4, 1846. Father Marion Bresillac was consecrated first bishop of Coimbatore. In honor of his patron saint, he dedicated the diocese and its cathedral to St. Michael. He also planned to model the cathedral after St. Peter's Basilica in Rome. He laid the foundation stone for the cathedral in 1850. The construction of the cathedral took 17 years and it was successfully completed with financial help from Propaganda Fide. The cathedral was blessed by Bishop Gladius Maria Depomier, the third bishop of Coimbatore, on April 28, 1867.
In 1870, Bishop Gladius Maria Depomier participated in the First Vatican Council. Father Joseph Bardou became the next bishop of Coimbatore from Aug. 23, 1874. When a severe drought swept Coimbatore from 1876-1878, he helped the people to a great extent by making porridge containers. He died on Feb. 7, 1903.
Coimbatore city is administered by a corporation headed by an elected mayor. The towns are managed by municipalities. The villages and small towns are administered by elected local bodies called panchayats.
The region is well connected by railway and roads. Coimbatore has its own airport.
The diocese enjoys a pleasant climate throughout the year as it is situated near the Western Ghats, a range of hills in South India.
The per capita income in the diocesan territory is Rs 23,515 ($533) as of January 2007. Farming, automobile-manufacturing, engineering and textiles are the major industries in the diocese. Cash crops such as cashew nuts, coffee, tea and spices are widely produced in the diocesan area.
Government and private operators provide extensive telecommunication facilities in the diocesan area. The diocese is well connected by local cable TV networks.
The literacy rate in the diocesan territory is 75.54 percent.