Recorded as O'Concannon and Concannon, this is an Irish surname of great antiquity, an din former times, considerable land holdings and authority. It is particulary associated with the west coast of the country and specificially County Galway. The origination is from the pre 10th century Gaelic O' Concheanainn, which means the decendants of Cuceannanm, a famous warrior and chief of Ui Maine, who is believed to have been killed in the year 991 a.d. The majority of Irish surname do originate from some famous or claimed famous person of ancient times. This is one whose origins seem to be proven and correct. It seems that for many centuries the clan O' Concannon were the lords of Ui Diarmarda in what is now Kilkerrin, County Galway. It is recorded that as late as 1585 the chiefs still occupied their seat of Kultullagh in the parish of Cormcamoe, although all trace of this castle now seems to have disappeared. As late as 1848 the chief of the clan still occupied lands in the parish of Kilkerrin, but by 1878 when the last comprehensive survey of Ireland was completed, they had disappeared from the list of landowners. In fact the clan itself has gradually shrunk, with the birth rate indicating only a membership of five hundred nameholders in modern Ireland from perhaps five thousand in past centuries.