Wild Horse Plains is a locality situated in South Australia on the eastern coastline of Gulf St Vincent. It is located approximately 69 kilometres north-northwest of the Adelaide city centre.
The area's boundaries were established in June 1997 and encompass the town of Wild Horse Plains, which was founded in 1881 on Port Wakefield Road, as well as the former Government Town of Lorne. The locality takes its name from Thomas Day, who observed wild horses grazing in the region around 1870.
Port Lorne Road serves as the primary access road to the former township of Lorne and defines much of the northern boundary of Wild Horse Plains.