Port Pirie (post code: 5540) is the sixth most populous city in South Australia after Adelaide, Mount Gambier, Whyalla, Murray Bridge and Port Lincoln. It is a seaport on the east coast of the Spencer Gulf, 223 km (139 mi) north of Adelaide.The settlement was founded in 1845 and is the site of the world's largest lead smelter, operated by Nyrstar. It also produces refined silver, zinc, copper and gold.