Donal MacCarthy Reagh of Kilbrittain (died 1636) was an Irish magnate who owned the extensive lands of Carbery (almost half a million acres) in south-western County Cork.
Donal was born the son of Cormac MacCarthy Reagh and Eleanor Fitzgibbon.
His father was the son and heir of Donal of the Pipes, 17th Prince of Carbery, but predeceased him.
Donal, the subject of this article, therefore inherited the lands of Carbery from his grandfather.
His father's family were the MacCarthy Reagh, a Gaelic Irish dynasty that branched from the MacCarthy-Mor line with Donal Maol MacCarthy Reagh, the first independent ruler of Carbery.
[1] His mother was a daughter of Edmund Fitzgibbon, 11th White Knight,[2] and widow of Florence MacCarthy of Iniskean.