Detached eight-bay single- and two-storey Early English Gothic-style Catholic cathedral, built 1843-57, on a cruciform plan on a corner site comprising five-bay double-height nave with five-bay single-storey lean-to side aisles to north and to south, single-bay (two-bay deep) double-height transepts to north and to south having single-bay single-stage tower to crossing on a square plan leading to single-bay double-height chancel to west (having single-bay single-storey flanking chapels) continuing into single-bay double-height apse on a half-octagonal plan.
An impressive large-scale cathedral of national significance built for Bishop William Kinsella (1793-1845) and Bishop Edward Walsh (fl. 1846-72) to designs prepared by William Deane Butler (c.1794-1857) possibly reworking an earlier (1836) submission by John Shaw (fl. 1820-42) using Gloucester Cathedral (begun 1089) as a source of inspiration. Exhibiting expert stone masonry throughout the various cut-limestone accents identify the elaborate Early English Gothic theme enhancing the architectural design value of the composition