William John Donthorn was an architect active, particularly in Norfolk, in the 19th century. He was born in 1799 at Swaffham in Norfolk, England and died on 18 May 1859 in Hastings. A tablet in Swaffham Church commemorates his life.
Colvin, Howard, A Biographical Dictionary of British Architects 1600-1840, 3rd edition (New Haven and London: Yale University Press, 1995), pp. 317-319.