Corcoran Families and their County Mayo and County Roscommon Ireland Connections
Corcoran wasn't in the top 25 most commonly documented surnames during the Griffith's Valuation. I think this is a good thing. Sometimes less is more! According to the 1890 Ireland Birth Indexes, 40 of the 121 recorded Corcoran births in Ireland took place in Connaught Province which includes the counties of Mayo, Sligo, Roscommon, Leitrim and Galway. The Corcoran surname was most prevalent in Mayo, Cork,Tipperary, Dublin and Kerry at this time.
The Griffith's Valuation which took place between 1855 and 1857 in County Mayo, shows the heaviest concentration of Corcorans by far in Tirawley Barony in North Mayo. There were 67 documented Corcoran land occupiers in Tirawley at this time. Carra Barony came in second with 19, Burrishoole Barony had 13, Gallen and Clanmorris Barony had 8 each, Kilmaine Barony had 10, Erris Barony had 6, and Murrisk Barony had 7; Costello Barony which borders County Sligo and County Roscommon was the only Barony without any Corcorans.
There were two civil parishes in Tirawley Barony that had large numbers of this surname, Addergoole with 18 and Crossmolina with 15. Keep in mind that whole undocumented families could be living with one land occupier and not listed. It is also important to remember that Griffith's Valuation was done in the period immediately following the peak of the famine. Many people had already immigrated or had died in preceeding years. A comparison between the Corcorans documented in the Roman Catholic Parish records pre-famine and the Griffith's Valuation post-famine would be the most accurate way to assess the true distribution of the Corcoran surname. Take a look at my Corcoran Surname Distribution Map for County Mayo, which documents where the Corcorans were living at the time Griffith's valuation was completed.
When the Griffith's Valuation was conducted for County Roscommon between 1855 and 1858, the Surname Corcoran was present in 24 different Civil Parishes that include: Athleague, Ardcarn, Baslick, Boyle, Bumlin, Cam, Cloonfinlough, Cloontuskert, Kilbride, Kilcolman, Kilgefin, Kilmeane, Killinvoy, Kilkeevan, Kilmore, Kilteevan, Kiltoom, Kiltrustan, Kiltullagh, Lissonuffy, Roscommon, St. Peter, Tibohine and Termonbarry. I will be documenting the individual Corcorans who occupied parcels in County Roscommon in all of the Civil Parishes noted in this list as I work my way through the valuation. (Griffith, 1847-1864; 2003, Roscommon).
The Irish Times website documented 82 Corcoran Households in County Roscommon when the Griffith's Valuation was conducted. (irishtimes.com, 2010, irish ancestors surname search, Brennan).
It is important to remember that Griffith's Valuation was done in the period immediately following the peak of the famine. Many people had already immigrated or had died in preceeding years. It did not document families, just individual land occupiers. More family members could have been living with them. I think that the most accurate way to assess the true distribution of the Corcoran surname, would be to compare the Roman Catholic Parish records pre famine with the post famine Griffith's Valuation. Unfortunately that analysis will have to wait until I work my way through the Catholic Parish microfilms.