Whyalla was founded as "Hummocks Hill", and was known by that name until 1916. It is the fourth most populous city in the Australian state of South Australia after Adelaide, Mount Gambier and Gawler and along with Port Pirie and Port Augusta is one of the three towns to make up the Iron Triangle. As at June 2018, Whyalla had an urban population of 21,742, having declined at an average annual rate of -0.75% year-on-year over the preceding five years. It is a seaport located on the east coast of the Eyre Peninsula and is known as the "Steel City" due to its integrated steelworks and shipbuilding heritage. The port of Whyalla has been exporting iron ore since 1903.