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.

The First Australian Imperial Force was the main expeditionary force of the Australian Army during the First World War. It was formed as the Australian Imperial Force (AIF) following Britain's declaration of war on Germany on 15 August 1914, with an initial strength of one infantry division and one light horse brigade. The infantry division subsequently fought at Gallipoli between April and December 1915, with a newly raised second division, as well as three light horse brigades, reinforcing the committed units.