New Zealand surveyor and pioneer farmer who assisted the geologist and naturalist Julius von Haast in his collecting in the West Coast region. Following his training, one of Young's first surveying assignments was on the Canterbury-Otago boundary searching for a pass to the West Coast with Edward Jollie. They explored this area in 1857-1859 but were unsuccessful. In 1862 Young joined a party including Julius von Haast (Canterbury Provincial Geologist) through Burkes Pass to Lakes Tekapo and Pukaki. The journey made them the first white men to visit Mt. Cook. Young travelled once more with Haast in 1863 riding to the western side of Lake Wanaka and venturing further north, where they discovered Haast Pass.

Haast was particularly pleased with Young, whom he described as a faithful and energetic companion who assisted him much with his botanical collecting. He requested that J.D. Hooker at Kew name any novelties found in the collections from the trip after Young, which he duly did, honouring him in four species names: Gnaphalium (Helichrysum) youngii, Agrostis youngii, Trisetum youngii and Triticum youngii. The Young Range and Young River are also named after him. He settled in Auckland with his wife in 1866 and then farmed at Kaipera Harbour (1868-1881) and Otakeho.

Sources:
E.J. Godley, 2000, "Biographical Notes (37): William Spearman Young (1842-1913)", New Zealand Botanical Society Newsletter, 59(March): 23-24.