The diocese's land area of 44,215 square kilometers covers civil districts of Belgaum, Bagalkot, Dharwad, Gadag and Haveri in Karnataka state, and Chandgad taluka of Kolhapur district in Maharashtra state.
Belgaum is one of the oldest, most prominent and culturally important place in the Western Ghats, one of India's three main watersheds. It lies in a zone of cultural transition from Karnataka, Maharashtra and Goa, with an easily traceable history back to the second century A.D. The nearest major cities to Belgaum are Panaji in Goa, Hubli and Dharwad in Karnataka, and Kohlapur in Maharashtra. Many Catholics in Belgaum trace their roots to Goa.
Konkani, Kannada, Marathi, English and Tamil are in use.
The diocese of Belgaum was erected on Sept. 19, 1953, by Pope Pius XII. Two civil districts of Belgaum and North Karnataka were separated from the archdiocese of Goa and two other civil districts of Dharwad and Bijapur were taken from the diocese of Pune to form the diocese of Belgaum.
Father Michael Rodrigues was appointed the first Bishop. Pope Paul VI separated North Karnataka district from the Belgaum diocese to form the diocese of Karwar on Jan. 24, 1976.