Murrough McMurrough O'Brien (1562 – July 24, 1597) was the 4th Baron Inchiquin

Baron Inchiquin

Baron Inchiquin is one of the older titles in the Peerage of Ireland. It was created in 1543 for Murrough O'Brien, Prince of Thomond, who was descended from the great high king Brian Boru)...

. He was the son of Murrough McDermot O'Brien, 3rd Baron Inchiquin

Murrough McDermot O'Brien, 3rd Baron Inchiquin

Murrough McDermot O'Brien was the 3rd Baron Inchiquin. He was the son of Dermod O'Brien, 2nd Baron Inchiquin and Margareth O'Brien and inherited his title in 1557 on the death of his father. He married Anabella Nugent, daughter of Christopher Nugent, 6th Lord Delvin; Murrough O'Brien, 4th Baron...

 and Annabelle Nugent. He married Margaret Cusack, daughter of Sir Thomas Cusack (Irish judge)

Thomas Cusack (Irish judge)

Sir Thomas Cusack was an Anglo-Irish judge and statesman of the sixteenth century, who held the offices of Master of the Rolls in Ireland, Lord Chancellor of Ireland, and Chancellor of the Exchequer of Ireland. He was one of the most trusted and reliable Crown servants of his time, but had a...

 of Cussington, Meath, Lord Chancellor of Ireland

Lord Chancellor of Ireland

The office of Lord Chancellor of Ireland was the highest judicial office in Ireland until the establishment of the Irish Free State in 1922. From 1721 to 1801 it was also the highest political office of the Irish Parliament.-13th century:...

 and his second wife Maud Darcy, and had one son; Dermod O'Brien, 5th Baron Inchiquin.

He was shot in 1597 when fording the River Erne near Sligo during the Irish wars. When half across the ford, a bullet passed under one arm and out at the other. He fell from his horse and drowned.

He was buried at Donegal Abbey and was succeeded by his son, then only 2 years old.