Salt production in South Australia has shown a steady expansion since inception of the industry in 1891 until it now (1971) exceeds 700 000 tonnes annually (valued at $2.75 million). Until 1966, over 80% of Australian production came from this State. However, proportion of the output derived from South Australia had fallen to 68% of the total in 1968 and to 35% in 1969 as a result of major developments in solar salt production in Western Australia. The local salt industry was based initially on lake deposits of a magnitude, purity and accessibility that were unrivalled in Australia and so situated climatically that the conditions for solar evaporation were exceptional. The numerous salt lakes of southern Yorke Peninsula were the principal sources of supply to the turn of the century. There, a comparatively high winter rainfall combined with dry, hot summers produced salt crusts ranging up to 10 em thick on the lake surfaces. By 1900 a number of companies were operating and production amounted to about 40 000 tonnes per year which, dependent upon seasonal fluctuation in output, represented the natural potential capacity of the district. Pre-eminence was later maintained through the establishment of artificial evaporating ponds based on seawater of higher than normal salinity and the introduction of mechanical harvesters. The first artificial salt fields were developed at Port Price during World War I. In 1940 I.C.I. Alkali (Australia) Pty. Ltd. commenced production of salt for the alkali industry at Dry Creek, 10 kilometres north of Adelaide, with the result that the State's output was more than doubled from 80 000 tonnes in 1939 to 171 000 tonnes in 1941. Expansion of these and other highly efficient fields has ensured a steady growth of the industry. The major producers are I.C.I. Australia Ltd. at Dry Creek, Ocean Salt Ltd. at Port Price, The Broken Hill Pty. Co. Ltd. at Whyalla and Waratah Gypsum Pty. Ltd. at Lake MacDonnell. Further developments have been foreshadowed in connection with a petrochemical industry which will be based on ethane and salt as raw feed stocks in the Port Augusta area. Elsewhere, in the more remote areas of the State there are large untapped reserves of salt in lake crusts and brines.