 On 21 January 1942 , Prime Minister John Curtin announced the war cabinet decision to name the newly constructed road Forrest Highway , for military purposes . Separately , the states ' nomenclature committees were considering names for the road . A proposal for a single name to be used in both states was put by the Western Australian committee to the South Australian committee when the highway was completed . Two names were suggested : Great Western Highway , in line with similar directional names in Western Australia , and Eyre Highway , after the explorer . After several communications between the committees , both decided to use the name Eyre Highway . After a receiving a letter from the South Australian Premier in May 1943 , supporting the nomenclature committee 's recommendation , Curtin agreed to the name , subject to approval from the Western Australian government . 
