It is located north of Clawdd Coch and Tredodridge in the community of Pendoylan in the Vale of Glamorgan, Wales.

[4] Samuel Richardson is said to have transformed the south front in the late 18th or early 19th century, by adding more castellations and corner turrets, but there is some doubt about this.

[11] Judge Jenkins was a man of great force of character and some eccentricity, named "Heart of Oak" and "Pillar of the Law".

He was impeached for high treason, and when an act was passed for his trial, he met it with a declaration that he would “die with the Bible under one arm and Magna Carta under the other”.

After the restoration of the monarchy under King Charles II, he was liberated in 1656 and returned to his estate in Glamorgan where he subsequently died and was buried at Cowbridge.

[24] This contained both coal and iron ore and was used to develop the Cyfarthfa Ironworks, that became the largest in the world and was later run by another resident of Hensol Castle, William Crawshay II.

In 1789 the estate was sold by the Talbot family to Samuel Richardson (1739–1824),[5][16] a banker,[27] who may have modified the south front of the house, and who was High Sheriff of Gloucestershire in 1787 and of Glamorgan in 1798.

[28] He is said to have been a pioneer in agriculture and made many improvements to the Hensol estate, including land drainage and introducing the threshing machine.

[31][34] In 1855, as Sir Benjamin Hall, Chief Commissioner of the Metropolitan Board of Works, he oversaw the later stages of the rebuilding of the Houses of Parliament, including the installation of the 13.8-tonne hour bell, "Big Ben", in the clock tower.

Their first son, Lieutenant Sir Rose Price (1878–1901) was killed in action at Villesdorp in the Anglo-Boer War.

Their third son Lt. William Rose Price (1882–1907) also died in South Africa, whilst serving in the 9th Queen's Royal Lancers.

[43] Their second son, Sir Francis Caradoc Rose Price (1880–1949) then inherited Hensol, but in 1923 he put it up for sale and was quoted in The Times newspaper as follows.

By the time one has paid all Imperial and local dues in the way of taxation there is not much left now, and for that reason I have decided to put the estate up for sale.

[46] Hensol hospital was opened in July 1930[47] as a "colony" for 100 men with learning disabilities ("mental defectives" in the terminology of the time).

New blocks were built in the grounds in 1935 to accommodate up to 460 men, women and children and in 1937 it was visited by Sir Kingsley Wood, Minister of Health.

At that time it housed 343 inmates and the Minister was reported as saying that he hoped to take back to his work in London fresh ideas which one could never obtain from minutes and records.

[49] Latterly in the 20th century, with the move towards community care for people with learning disabilities, the number of patients progressively decreased.

The interior of Hensol Castle was used to stand-in for parts of Whitehall in the 1992 film Rebecca's Daughters and was used for scenes set in 10 Downing Street for the Doctor Who episodes "Aliens of London", "World War Three" and "The Sound of Drums".