William Flower, 1st Baron Castle Durrow

William Flower, 1st Baron Castle Durrow PC (Ire) (11 March 1685 – 29 April 1746) was an Anglo-Irish peer and politician.

Political career
He sat as Member of Parliament (MP) for County Kilkenny from 1715 to 1727. Subsequently, he represented Portarlington until 1733, when he was raised to the peerage as "Baron Castle Durrow, of Castle Durrow in the County of Kilkenny". (At the time the manor of Durrow was an exclave of County Kilkenny; in 1842 it was transferred to Queen's County, later known as Laois.)

Flower was made High Sheriff of County Kilkenny in 1731, and was invested to the Privy Council of Ireland in 1735.

He owned a substantial property at Abercynrig in Brecon. He inherited it from his stepmother, the Welsh heiress Dorothea Jeffreys. She was the only daughter of Colonel John Jeffreys, first Master of the Royal Hospital Kilmainham, and widow of Arthur Turner (died 1684), judge of the Court of Common Pleas (Ireland). He built Castle Durrow, Durrow, County Laois, as his principal Irish residence: the family remained there until 1922.

Jonathan Swift praised him as "a gentleman of very good sense and wit".

Family
He was the only son of Thomas Flower of Finglas and his first wife Mary Temple, daughter of Sir John Temple, Speaker of the Irish House of Commons, and Jane Yarner. His paternal grandparents were Sir William Flower, MP and Privy Councillor, and Frances Weldon. Flower was educated at Christ Church, Oxford. He succeeded to his father's estates in 1700.

In 1717, Flower married Edith Caulfeild, daughter of Hon. Toby Caulfeild, a son of the 1st Viscount Charlemont and Rebecca Walsh. They had two daughters and two sons. His daughter Rebecca, married James Agar, a prominent County Kilkenny politician, and was the mother of six children, including George Agar, 1st Baron Callan.

Flower died in 1746 aged 61 and was buried at Finglas in County Dublin. His only surviving son Henry succeeded to the barony. and became the first Viscount Ashbrook in 1751.