1865 saw Bathurst become a separate Diocese with the appointment of Dr Matthew Quinn was the first Bishop. The area covered by the Diocese changed little from when it was a mission in 1841, which extended from the River Murray to Queensland, and from the Blue Mountains to the border of South Australia, except that in on 10 May 1887 it lost territory to establish the Roman Catholic Diocese of Wilcannia, to which more territory was lost in 1917, when it was renamed Roman Catholic Diocese of Wilcannia-Forbes.