Peterborough and Orroroo are both on the edge of Goyder's Line. Goyder's Line is an imaginary line marking off a huge area of inland South Australia that receives an average of 254 millimetres of rainfall a year or less. It was named after George Woodroffe Goyder (1826-1898), who was born in England and migrated to Australia in 1848. In 1857 he was sent off to check on some geographical discoveries of Benjamin Babbage, the South Australian Government Assayer. Between Babbage's earlier journey north and Goyder's trip there had been some heavy rainfalls and the countryside was in full flower. Goyder, in contradiction of earlier assessments by Edward Eyre, was able to report with some amazement that Lake Blanche contained fresh water and that the land was fertile. But he was a 'bit green' and easily deceived by this temporary lushness. As a result of his optimistic account there was a rush of applications for leases in this 'promised land'. It was not long, however, before these pioneers of the north were sending back gloomy reports on the barren, waterless and useless tracts of land. Following some years of drought, in 1865 Goyder was sent north to determine the line of demarcation between where rainfall had extended and where the drought conditions prevailed. Thus was established the so-called “Goyder's line of rainfall” which followed the southern boundary of the vast saltbush areas of the north. Goyder's Line provides a very accurate guide to the separation point between lands suitable for all sorts of agriculture on a long term basis and lands suitable for grazing. Those settlers who did not listen to the advice of Goyder eventually were forced to leave their holdings to the pastoralists and take up land elsewhere.