'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 century
Ainglioch Ó Dónalláin, poet, fl. mid-14th or mid-15th century
Flann Óge Ó Domhnalláin, Chief Poet of Connacht, died 1342
Mael Sechlainn Ó Domhnalláin, Irish poet, died 1375
Flann Óc mac Séoan Ó Domhnalláin, Ollamh Síol Muireadaigh, 1404
Nehemiah Donnellan, Archbishop of Tuam, fl. c. 1560-1609
James 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 director
John Donnellan, Irish politician
Keith Donnellan, philosopher
Michael Donnellan, various including
Michael Donnellan, Irish Clann na Talmhan politician
Michael Donnellan, GAA footballer
Nanci Donnellan, sports radio broadcaster
Philip Donnellan, English documentary film-maker
Steve Donnellan, Australian evolutionary biologist
Thomas Donnellan, Roman Catholic Archbishop of Atlanta, 1968-1987
