William Rounsevell (c. 1816 – 5 October 1874)[1] was a businessman of Cornish origins who founded a livery stable and mail coach business in the early years of colonial South Australia. His sons John Rounsevell (c.1836–1902) and Ben Rounsevell (1842–1923) were prominent businessmen, pastoralists and politicians in South Australia.