 On 5 August 1951 the seat of the diocese was moved from Port Augusta to Port Pirie, with the name of the diocese being also changed.In terms of geographic size the Diocese of Port Pirie is Australia's second largest diocese (after Darwin) and one of the largest in the Southern Hemisphere.The diocese measures 978,823 km2, which is made up of the largest portion of South Australia and the southern parts of the Northern Territory.