Brennan Families and their County Mayo and County Roscommon, Ireland Connections

Brennan was one of the 20 most commonly documented surnames during the Griffiths Valuation. According to the 1890 Birth Indexes of Ireland, 94 of the 358 total Brennan births recorded in Ireland, took place in the Connaught area of Ireland which includes the counties of Mayo, Galway, Roscommon, Leitrim and Sligo. The surname Brennan was most prevalent in Kilkenny, Dublin, Sligo, Mayo, Carlow and Roscommon at the turn of the century, while Brannan and Brannon were found primarily in Donnegal. (Matheson, 1982, p. 7,39).

The Griffith's Valuation, which took place around 1857 in County Mayo, shows the heaviest concentration of Brennan's in Costello Barony. The Valuation documented 80 Brennan's occupying land in Costello Barony, 47 in Gallen Barony, 46 in Carra Barony, 9 in Clanmorris Barony, 5 in Burrishoole Barony, 4 in Kilmaine Barony, 4 in Murrisk Barony, and 1 in Erris Barony. Kilconduff civil parish in Gallen Barony had the highest number of Brennan land occupiers at 29.

When the Griffith's Valuation was conducted in County Roscommon between 1855 and 1858, the Surname Brennan was present in 46 different Civil Parishes, the Surname variation Brannon in two and Surname variation Brannan in four Civil Parishes. Brennans were present in Ardcarn, Athleague, Ballintober, Baslick, Boyle, Bumlin, Cloonfinlough, Clooncraff, Cloontuskert, Cloonygormican, Creeve, Elphin, Estersnow, Fuerty, Kilbride, Kilbryan, Kilcolagh, Kilcooley, Kilcorkey, Kilgefin, Kilglass, Kilkeevin, Killinvoy, Killukin, Killummod, Kilmacumsy, Kilmeane, Kilmore, Kilnamanagh, Kilronan, Kilteevan, Kiltoom, Kiltrustan, Kiltullagh, Lissonuffy, Rahara, Roscommon, Shankill, St. John, ST. Peter, Tachmaconnell, Taghboy, Termonbarry, Tibohine, Tisrara and Tumna. Brannons were in Kilcorkey and Kiltullagh Civil Parishes and Brannans were present in Fuerty, Kilronan, Kilcolman and Ardcarn Civil Parishes. (Griffith, 1847-1864; 2003, Roscommon). I will be documenting each individual Brennan that was recorded in the County Roscommon Griffith's Valuation as I work my way through the records. The Irish Times website documented 255 Brennan Households in County Roscommon when the Griffith's Valuation was conducted. (, 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 Brennan 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.

There is a great article on the Brennans of Connacht on the Leitrim-Roscommon Genealogy Website that is extremely detailed and definitely worth checking out!