Donnellan

Donnellan is an Irish surname and refers to the clan name Ó Domhnalláin or O'Donnellan. 
At least two unrelated families of the name existed in Gaelic Ireland. One in south-east Ulster, another in south-east Connacht in the kingdom of Ui Maine. 
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: