Ironstone is a locality in South Australia located on the north coast of Dudley Peninsula on Kangaroo Island overlooking Backstairs Passage about 107 kilometres (66 mi) south of the Adelaide city centre and about 3 kilometres (1.9 mi) east of Penneshaw. Its boundaries were created in March 2002 while its name was derived from Ironstone Hill, a hill located within its boundaries. The locality includes the following places which are listed on the South Australian Heritage Register: Bates Farmhouse and Threshing Floor (Ironstone)