Kilmacrenan (Irish: Cill Mhic Réanáin), sometimes spelled Kilmacrennan, is a barony in County Donegal, Ireland.

[1][2][3] Baronies were mainly cadastral rather than administrative units, which acquired modest local taxation and spending functions in the 19th century before being superseded by higher units under the Local Government (Ireland) Act 1898.

[4] Kilmacrenan is the largest barony in Ireland by land area.

Kilmacrenan takes its name from Kilmacrenan village, in Irish Cill Mhic Réanáin or 'Cill Mhic nÉanáin, "church of the sons of Eanan.

[7] Kilmacrenan was the ancient territory of the O'Donnell kings of Tyrconnell, O'Breislein (O'Breslin), Mac Sweeneys, O'Begley, O'Friel,[8] O'Kernaghan of Clondavaddog, McCoyle of Mevagh, O'Toner of Tullyfern and O'Laherty (Laverty).