Peacock was the son of Ralph Peacock, a mines supervisor from Swaledale, Yorkshire, and Dorothy Robinson. He was married twice, firstly to Hannah Crowther, and secondly to Frances Littlewood. At the time of his death his eldest son, Colonel Ralph Peacock
VD (1838–1928) of the part-time
Manchester Artillery Volunteers, succeeded him at Gorton Foundry. Of his daughters the eldest, Jane Peacock (1855–1928), married William Taylor Birchenough JP, a silk manufacturer who was elder brother of Sir
Henry Birchenough and son of
John Birchenough. Peacock's grandson, Richard Peacock Birchenough, married Dorothy Grace Godsal, daughter of
Philip Thomas Godsal, the inventor of the Godsal anti tank rifle. Peacock's youngest daughter, Eugenie, married George P. Dawson, who succeeded Colonel Peacock as managing director on the formation of the
incorporated Beyer, Peacock and Company Limited in 1902. Colonel Ralph Peacock died without issue, as did Richard Peacock's only other surviving son, Frederick William Peacock (1858–1924). at Brookfield Unitarian Church Richard Peacock died in Manchester at the age of 68. He is buried in the
Peacock Mausoleum in the graveyard of his
Brookfield Unitarian Church. The graveyard also holds the remains of Ralph Peacock and an earlier deceased son, Joseph Peacock. ==References==