General Sir Henry Errington Longden KCB CSI (14 January 1819 – 29 January 1890) was a British Army officer who served as Adjutant-General in India.

Educated at Eton College and the Royal Military College, Sandhurst, Longden was commissioned into the 10th Regiment of Foot on 16 September 1836.

[2] He fought at the Battle of Sobraon in February 1846 during the First Anglo-Sikh War as well as the Siege of Multan in Autumn 1848 and the Battle of Gujrat in February 1849 during the Second Anglo-Sikh War.

[2] He also took part in the Siege of Lucknow in Autumn 1857 and the subsequent relief of Azamgarh during the Indian Rebellion.

[6] He was appointed a Companion of the order of the Star of India on 28 May 1870.