Domnall Remur (d. 1041), son of Donnchad, a prominent Leinster dynast, belonged to the ruling lineage of Uí Chennselaig. Domnall, dubbed Remur (‘the fat’), was a brother of Diarmait (qv) son of Máel na mBó. Their father Donnchad (qv), known as Máel na mBó, had been a contender for the kingship of Leinster but was slain in an internecine conflict in 1006; their mother was Aífe, daughter of Gilla-Pátraic, king of Osraige.
From the early 1030s onwards Domnall and Diarmait were fighting for the overkingship of Leinster against the sons of Dúnlaing (qv) son of Tuathal (qv), who belonged to the rival dynasty of Uí Muiredaig. They were, through another marriage of their mother's, half-brothers of Echdonn, who in turn was brother and tánaise (heir-apparent) to Murchad (qv) son of Dúnlaing. In 1041 Domnall, styled rígdamna Ua Cennselaig (eligible for the kingship of Uí Chennselaig), led an attack on the territory of Uí Bairrche (the Carlow–Laois border area) as part of an offensive against Uí Muiredaig. Returning to his home territory, he was overtaken at Cell Mo Lappóc (in Co. Carlow) and slain by Murchad.
Domnall's son Donnchad was a contender for the kingship of Dublin in 1072 and, although suppressed by Tairdelbach Ua Briain (qv), re-emerged after the latter's death in 1086 and granted the lands of Clonkeen to the cathedral of the Holy Trinity. Domnall's descendants adopted the surname of Ua Domnaill and featured as rulers of Uí Fhelmeda (in Co. Carlow), and occasionally as kings of Uí Chennselaig.