Alan Ian Percy, 8th Duke of Northumberland, was born 17 April 1880 in London, England, United Kingdom to Henry George Percy, 7th Duke of Northumberland (1846-1918) and Edith Campbell (1849-1913) and died 23 August 1930 London, England, United Kingdom of unspecified causes. He married Helen Magdalan Gordon-Lennox (1886-1965) 18 October 1911 .
Children
| Name | Birth | Death | Joined with |
| Henry George Alan Percy, 9th Duke of Northumberland (1912-1940) | 15 July 1912 | 21 May 1940 Pecq, Hainaut Province, Wallonia, Belgium | |
| Hugh Algernon Percy, 10th Duke of Northumberland (1914-1988) | 6 April 1914 London, Greater London, England, United Kingdom | 11 October 1988 Brentford, Greater London, England, United Kingdom | Elizabeth Diana Montagu-Douglas-Scott (1922-2012) |
| Elizabeth Ivy Percy (1916-2008) | 25 May 1916 St. George Hanover Square, Greater London, England, United Kingdom | 16 September 2008 Haddington, East Lothian, Scotland, United Kingdom | Douglas Douglas-Hamilton, 14th Duke of Hamilton (1903-1973) |
| Diana Evelyn Percy (1917-1978) | |||
| Richard Charles Percy (1921-1989) | |||
| Geoffrey William Percy (1925-1984) | |||
Footnotes (including sources)
| ‡ General |
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