'Donnellan is an Irish surname and refers to the clan name Ó Domhnalláin or O'Donnellan.
At least two unrealated families of the name existed in Gaelic Ireland. One in south-east Ulster, another in south-east Connacht in the kingdom of Ui Maine. A very well known family named the O'Donnellan's lived in the same county in Ireland as the Donnellan's. They are family members, but the Donnellan's kept their last name unlike the O'Donnellan's that switched their last name when entering the United States to Donlin.
The patron of the Donnellan's of Ui Maine is Saint Grellan. The family derive their name from Domnallan mac Maelbrigdi.
Donnellan may refer to:
Domnallan mac Maelbrigdi of Ui Maine, ancestor of the Donnellans of Galway, fl. c. 9th/10th centuryAinglioch Ó Dónalláin, poet, fl. mid-14th or mid-15th centuryFlann Óge Ó Domhnalláin, Chief Poet of Connacht, died 1342Mael Sechlainn Ó Domhnalláin, Irish poet, died 1375Flann Óc mac Séoan Ó Domhnalláin, Ollamh Síol Muireadaigh, 1404Nehemiah Donnellan, Archbishop of Tuam, fl. c. 1560-1609James Donnellan, lawyer and politician, c. 1588 - 1665.Pádhraic Ó Domhnalláin, Irish duelist, fl. 1830.Padraig Ó Domhnallain, short-story writer, born 1884.Seosamh Ó Dónalláin, Irish Republican Army, died 1920.Martin Donnellan, recipient of the Scott Medal, born 1948.Declan Donnellan, theatre directorJohn Donnellan, Irish politicianKeith Donnellan, philosopherMichael Donnellan, various includingMichael Donnellan, Irish Clann na Talmhan politicianMichael Donnellan, GAA footballerNanci Donnellan, sports radio broadcasterPhilip Donnellan, English documentary film-makerSteve Donnellan, Australian evolutionary biologistThomas Donnellan, Roman Catholic Archbishop of Atlanta, 1968-1987
