MacCarthy Reagh (Mac Carthaigh Riabhach), Domhnall Glas (d. 1442), lord of Carbery, was probably the eldest son of Domhnall Riabhach MacCarthy (qv), lord of Carbery. Fragmentary evidence suggests that throughout his life he had to struggle to maintain his power against the MacCarthy Mór dynasty, the FitzGeralds of Desmond, and familial rivals. In 1421 his son Cormac na Coilleadh was killed in an ambush while attempting to attack the lands of the MacCarthy Mór; a swift response by Domhnall Glas forced the MacCarthy Mór to withdraw. By 1430 Domhnall Glas was beset by internal dynastic problems, as his brother and eventual successor, Donnchadh MacCarthy Reagh (d. 1453), joined James FitzGerald (qv), 7th earl of Desmond, in an assault on Carbery. During the course of the campaign Domhnall Glas's castle of Kilbritton fell to Desmond, who handed it over to Donnchadh and installed him as lord of Carbery; however, Domhnall Glas quickly reestablished himself upon Desmond's departure. Nothing else is known of his career. He died in 1442, and was succeeded by Donnchadh, whose reign is also obscure. When Donnchadh died in 1453, he was described as ‘the best general protector to the men of Ireland and Scotland’. He was succeeded as lord of Carbery by another brother, Diarmaid an Dúna MacCarthy (qv).
AFM, iv, 881, 925, 983; AU, iii, 91, 111; ‘Mac Carthaigh's Book’, Misc. Ir. Annals, 111; NHI, ii, 582, ix, 157