Flann mac Congalaig was a King of Brega from the Uí Chonaing sept of Cnogba (Knowth) of the Síl nÁedo Sláine branch of the southern Ui Neill. He was the son of Congalach mac Conaing, a previous king. He ruled from 786 to 812.
- Position held
- Kings of Brega
- Died
- 812
