The Hon. Lady Emma Cecilia "Ida" Darwin (née Farrer; 7 November 1854 – 5 July 1946) was an English mental health campaigner.
Born in Dorking, Surrey, in 1854, she was the daughter of the statistician Thomas Farrer of Abinger Hall (later Baron Farrer) by his first wife, Frances Erskine (1825–1870), daughter of the historian and orientalist William Erskine (1773–1852).
- Erasmus Darwin IV (7 December 1881 – 24 April 1915) who was killed in the Second Battle of Ypres during the First World War.
- Ruth Frances Darwin (1883–1972), married Dr William Rees-Thomas, was a notable advocate of eugenics.
- Emma Nora Darwin (1885–1989) edited the 1959 edition of The Autobiography of Charles Darwin and married the civil servant Sir Alan Barlow.
Along with her husband, she helped found the Central Association for Mental Welfare (CAMW) in 1913.
The Ida Darwin Hospital in Cambridge is named for her.
She is buried at the Parish of the Ascension Burial Ground in Cambridge with her husband.
Forms of address:
- Miss Ida Farrer (1854-1880)
- Mrs Ida Darwin (1880-1893) - her marriage
- The Hon. Mrs Ida Darwin (1893-1918) - her father's barony.
- The Hon. Lady Ida Darwin (1918-1946) - her husband's knighthood.
- Births, Deaths, Marriages and Obituaries . Freeman's Journal and Daily Commercial Advertiser (Dublin, Ireland), Thursday, January 8, 1880
- Burke's Landed Gentry, Darwin formerly of Downe.
- CWGC :: Casualty Details at www.cwgc.org
- The Times, Saturday, Jul 06, 1946; pg. 7; Issue 50496; col E
- Leslie Scott KC Hon. Lady Darwin. Obituaries, The Times, Tuesday, Jul 16, 1946; pg. 7; Issue 50504; col E
- Gwen Raverat, 1952. Period Piece