Henry Pelham Fiennes Pelham-Clinton, 5th Duke of Newcastle-under-Lyne, KG, PC (22 May 1811 – 18 October 1864), styled Earl of Lincoln before 1851, was a British politician and aristocrat.

Newcastle was the son of Henry Pelham-Clinton, 4th Duke of Newcastle-under-Lyne, by his wife Georgina Elizabeth, daughter of Edward Miller-Mundy.

[1] Newcastle was returned to Parliament for South Nottinghamshire in 1832, a seat he held until 1846, and then represented Falkirk Burghs until 1851, when he succeeded his father in the dukedom.

Initially a Tory, he served under Sir Robert Peel as First Commissioner of Woods and Forests from 1841 to 1846 and as Chief Secretary for Ireland in 1846, as the effects of the Great Irish Famine began to take hold.

[1] From 18 June 1859 to April 1864, he served as Secretary of State for the Colonies in Lord Palmerston's Liberal administration.

[2] In 1849, the chief surveyor of the Canterbury Association, Joseph Thomas, named the future town of Lincoln in New Zealand after him.