William Wentworth-Fitzwilliam, Viscount Milton (27 July 1839 – 17 January 1877) was a British explorer and Liberal Party politician.
Fitzwilliam was the eldest son of William Wentworth-FitzWilliam, 6th Earl FitzWilliam, and his wife Lady Frances Harriet, daughter of George Douglas, 17th Earl of Morton, and was educated at Eton and Trinity College, Cambridge. He was epileptic.
Arriving in Quebec City in July 1862, Milton and Dr Walter Butler Cheadle traveled across the North American continent, wintering near Fort Carlton. After a challenging and at times humorous summer they reached Victoria, BC. Together with Butler Cheadle, he traveled up the Athabasca River and in 1863 they became the first "tourists" to travel through the Yellowhead Pass.
They later co-authored "The North-West Passage by Land" and " Voyage de l'Atlantique au Pacifique, à travers le Canada", which described their expedition in considerable detail.
Following his adventure in Canada, Milton entered politics and became one of the youngest members of the House of Commons. He represented the West Riding of Yorkshire South between 1865 and 1872.
On 10 August 1867, in London, Lord Milton married Laura Maria Theresa Beauclerk (3 January 1849 – 30 March 1886 Wentworth Woodhouse), daughter of Lord Charles Beauclerk, son of the William Beauclerk, 8th Duke of St Albans. They had one son and three daughters;