History of Tuam Diocese
The Archdiocese of Tuam, the metropolitan see of Connacht, extends, roughly speaking, from the Shannon westwards to the sea, and comprises half of County Galway, and nearly half of Mayo, with a small portion of south Roscommon. It is territorially the largest diocese in Ireland, including in itself about one-fourteenth of the entire area of the country. At the census of 1901 the Catholic population was 193,768; the entire non-Catholic population was 4,194. There are several parishes in which all the inhabitants are Catholics. The mainland portion of the archdiocese is divided by a chain of lakes extending from the city of Galway to the Pontoon, near Foxford, Mayo. The largest of these lakes - Corrib, Mask, and Carra - form a magnificent and continuous watercourse, but are not connected by navigable rivers or canals. The country east of these lakes is a great undulating plain, mostly of arable land, interspersed here and there with bogs and smaller lakes. The country west of the great lakes is of entirely different character. It is nearly all rugged and heathery, with ranges of hills rising steeply from the lakes, especially from the shores of Lough Mask on one side, and from the shores of the Atlantic Ocean on the other, forming many lofty peaks with long-drawn valleys where the streams rushing down widen into deep and fishful lakes, which, especially in Connemara, attract fishermen from all parts of the United Kingdom. The population of this rugged lakeland is sparse and poor, but the scenery very picturesque, especially towards the west, where the bays of the ocean penetrate far in between the mountains, as at the beautiful Killary Bay. This western coast is bordered by many wind-swept islands, affording a precarious sustenance to the inhabitants. Of these the chief are the Isles of Aran in Galway Bay, and farther off, on the north-western coast, Inishark, Inisboffin, and Inisturk, Clare Island and Achill Island - all of which are inhabited and have schools and churches. There are three priests on the Aran Islands, one on Inisboffin, one on Clare Island, and three on Achill, which has a population of about 6000 souls.
The Archdiocese of Tuam stretches from the shores of Achill Island to the low lying fields of Athenry, making it the largest diocese in the country. Geographically split north/south by the two lakes, Loughs Mask and Corrib, Tuam has pastoral charge of the largest Gaeltacht area in the country and of six of Ireland's island parishes. It also contains the major pilgrimage centres of Knock Shrine and Croagh Patrick. Established by the twelfth-century synods of Rathbreasail and Kells, it subsequently absorbed two other medieval dioceses: Annaghdown and Mayo.
There are 56 parishes in the Tuam Archdiocese which is gathered into 8 deaneries. More information on each parish including local amenities and mass times can be found here.