Domnall mac Cellaig (died 728) was a King of Connacht from the UàBriúin branch of the Connachta. He was the son of Cellach mac Rogallaig (died 705), a previous king. The sept of Ui Briun he belonged to was the SÃÂl Cellaig of Loch Cime.
Domnall has been omitted from the king-lists but his reign is attested in the annals. He succeeded Indrechtach mac Muiredaig Muillethan (died 723) as king and ruled 723âÂÂ728. His son Flaithràmac Domnaill (died 779) was also a king of Connacht.