The Pentropic organisation was a military organisation used by the Australian Army between 1960 and 1965. It was based on the United States Army's pentomic organisation and involved reorganising most of the Army's combat units into units based on five elements, rather than the previous three or four sub-elements. The organisation proved unsuccessful, and the Army reverted to its previous unit structures in early 1965.

The 1st Division, also known as the 1st (Australian) Division, is headquartered in Enoggera, a suburb of Brisbane. The division was first formed in 1914 for service during the First World War as a part of the Australian Imperial Force (AIF). It was initially part of the Australian and New Zealand Army Corps (ANZAC) and served with that formation during the Gallipoli campaign, before later serving on the Western Front. After the war, the division became a part-time unit based in New South Wales. During the Second World War it undertook defensive duties in Australia. It was disbanded in 1945.