The Castle Howard Arboretum is an arboretum situated near Malton in North Yorkshire, England. It is run as a joint enterprise between Castle Howard Estates and Royal Botanic Gardens, Kew. Originating in 1979, it comprises more than 7,000 trees, including some that are rare or endangered, across a site of .
The walling to the south of the arboretum was designed by John Vanbrugh, and is in limestone. The wall is about high, it extends for about , and has a plinth, buttresses and tapering upper courses. The wall contains square and circular interval towers of varying designs. It is grade I listed.