Murphy's Haystacks are inselberg rock formations located at Mortana, between Streaky Bay and Port Kenny on the Eyre Peninsula in South Australia. They obtained their name because a traveller in a coach saw the formation in the distance. He asked how a farmer could produce so much hay. As the farm was on a property owned by a man called Murphy, the rocks became known as Murphy's Haystacks.
The site is listed on the South Australian Heritage Register.