Donnchad Donn mac Flainn | |
|---|---|
| Died | 944 |
| Other names | Duncan of the Brown Hair |
| Occupation(s) | High King of Ireland, King of Mide |
| Term | 919–944 (High King of Ireland), 919–944 (King of Mide) |
| Predecessor | Niall Glúndub (High King of Ireland), Conchobar mac Flainn (King of Mide) |
| Successor | Congalach Cnogba (High King of Ireland), Oengus mac Donnchada (King of Mide) |
| Spouse(s) | Cainnech ingen Canannán, Órlaith íngen Cennétig, Dub Lémna ingen Tighearnáin |
| Children | Conn, Óengus, Domnall Donn, Flann, Óebfhinn |
| Parent(s) | Flann Sinna (father), Gormlaith ingen Flann mac Conaing (mother) |
| Relatives | Gormflaith ingen Flann Sinna (sister) |
Donnchad Donn mac Flainn (Duncan of the Brown Hair, son of Flann) (died 944) was High King of Ireland and King of Mide. He belonged to Clann Cholmáin, a branch of the southern Uí Néill.