Colonel Hercules Arthur Pakenham CMG DL JP (17 February 1863 – 28 March 1937) was a unionist politician in Northern Ireland. A member of the Pakenham family headed by the Earl of Longford, he was the eldest son of Lieutenant-General Thomas Pakenham, by Elizabeth Clarke, daughter of William Clarke, of New York City. He was educated at Eton and the Royal Military College Sandhurst from which he was commissioned as an officer in the Grenadier Guards in 1883. He held posts as aide de camp to the Governor General of Canada from 1886 to 1888, and to the Governor General of India from 1888 to 1893. The following year he was promoted to captain on 12 September 1894. In 1898 he was promoted to the rank of major in the 4th (Militia) Battalion of the Royal Irish Rifles. He acted as private secretary