By the kind permission of Bishop Kelly of Achonry and Father Gavigan, Adm., friends and members of our Association from across the Country made a pilgrimage to the Cathedral of the Annunciation and Saint Nathy for the feast of the Assumption. The Mass was offered for the late Bishop Thomas Flynn of Achonry who had been a great friend to the Gregorian Rite. By a beautiful coincidence, we were met by the Bishop and the Religious of the Diocese who were there to celebrate the Year for Consecrated Life.
Ballaghaderreen is the only Parish of the Diocese of Achonry in the County of Roscommon, although it was part of County Mayo until an Act of the British Parliament in 1859.
The Cathedral was designed for Bishop Patrick Durnin of Achonry (1852-1875) about 1855 by the English architects Matthew Ellison Hadfield and George Goldie. The Civil Engineer and Architect's Journal 19 (Oct 1856), 325 (illus., Pl. XXIX) described it as: "New cathedral in Early English style. It was commenced some three or four years ago, and after laying the basement course, the works were suspended under the direction of the above named firm [Weightman, Hadfield & Goldie]. The plan consists of a spacious nave and aisles, chancel, side chapels, western tower and sacristy. The proportions of these various portions were already determined before Messrs. Weightman and Co. commenced operations, and they have been in consequence very much crippled in carrying out their design."
It was consecrated on 3rd November, 1860. The site was donated by Lord Dillon and the local blue limestone came from quarries on his estate. The High altar is by Henry Lane of Dublin. The Dillons were prominent in the National struggle. The newspaper The Nation, was co-founded by John Blake Dillon with Thomas Davis and Charles Gavin Duffy.