Find Irish Catholic ancestors faster at Ancestry's Ireland, Catholic Parish Registers, 1655-1915. . Find all ancestors on Ancestry's Irish databases for free during March.
Last July the National Library of Ireland posted images of the registers at http://registers.nli.ie/. There's a description of the project and resulting digital images, approximately 373,000 of them at http://registers.nli.ie/about.
In February Ancestry and Findmypast both announced an index to the registers would be coming in March. It appeared to be a bit of a horse race.
Ancestry is first out of the starting gate, by a nose, with a database called Ireland, Catholic Parish Registers, 1655-1915. Ancestry's figures are 25,631,162 records in about 1 million events in 366,858 images from approximately 94% of Catholic parishes. Many of the originals are difficult to read so expect indexing issues ,and there are gaps in the records.
The bar chart shows the number of events recorded for the decade centred on the year specified. Note that coverage after the decade of the 1870s declines dramatically.
Free access during the whole of March is in recognition of St Patrick's Day and the 1916 Easter Rising centenary,