The diocese covers 37% of New South Wales, including the Riverina and the far west of the state.

The diocese has 23 parishes and covers main population centres of Griffith, Broken Hill, Deniliquin, Leeton, Narrandera and Corowa.

Initial ground work for the cathedral building begun as early as 1937, but substantive construction was not until 1954 and the foundation stone being laid in 1954.

However, the building did not actually become the cathedral until 1984 as part of the diocese's centenary celebrations.

The cathedral was invested in honour of the World War II fallen and in 1956 the Archbishop of Brisbane dedicated the cathedral's honour roll.