1,105 in Co. Roscommon.
120 in Co. Longford.
1,932 in Co. Kelkenny.
563 in Co. Kerry.
In the Irish Census 1911, there are 14,571 people recorded with the family name Brennan.
918 in Co. Roscommon.
133 in Co. Longford.
1,891 in Co. Kilkenny.
527 in Co. Kerry.
You are probably wondering why I have chosen Roscommon, Longford, Kilkenny and Kerry. I have found my father's family on Clawinch Island in Co. Longford in 1850 in Griffith's Valuation. My father grew up in Co. Roscommon. Family stories say that the Brennans were kicked out of Kilkenny by Cromwell in the 1600's and there are Brennans here in Kerry where I live who are not related to us... or so I was always told.