 Ayr and Cambridge were not used in the 1834 counties, taking up area which is approximately in what became Macquarie County and Brisbane County.Instructions were given to Governor Brisbane in 1825 to survey New South Wales and divide it into counties of various sizes, hundreds, and parishes between 15 and 25 square miles (40 and 65 km²).The Nineteen Counties were surveyed by Thomas Mitchell in 1834.