11th Australian Infantry Battalion

After the First World War the defence of the Australian mainland lay with the part-time soldiers of the Citizens Military Force (CMF), also known as the Militia. The Militia was organized to maintain the structure of the First AIF and kept the same numerical designations. The Militia units were distributed in the same areas the original AIF units were raised and known by the name of their shire. Thus, Perth's 11th Infantry Battalion was the "City of Perth Regiment". However, during the 1930s little was spent on defence and the Militia had few volunteers. The 11th Battalion merged with the 16th Infantry Battalion to form the 11th/16th Infantry Battalion but later separated in 1936 to once again become the 11th.

Like the other battalions in the Western Australia's 13th Brigade (the 16th and 28th Battalions), the 11th primarily spent the Second World War carrying out garrison duties. As part of the 4th Division, the 13th Brigade remained in Western Australia and during the second half of 1942 was III Corps' main infantry force. III Corps was responsible for the state's defence. In 1943 the 13th Brigade moved to the Northern Territory, where the 11th was based at Adelaide River and then later in the Darwin area. The brigade's commander, Brigadier Eric George Henderson McKenzie, held the longest command of a brigade during the war. McKenzie took over the brigade in June 1940 and relinquished command in May 1945 due to illness.

The long period of garrison work eventually ended when the 13th Brigade became part of the 5th Division and sailed to New Britain from the end of November 1944. The 11th Battalion reached Jacquinot Bay on 3 December. The brigade remained at Jacquinot Bay until the middle of April 1945, when it relieved the 6th Brigade at Wide Bay.

Rather than carry out a major offensive, the Australian force confined the Japanese to Rabaul and the Gazelle Peninsula with active patrolling. The 6th Brigade established the line across the Gazelle Peninsula, by patrolling between Open and Wide Bay. The 13th Brigade held and patrolled the line. From 14 April to the end of the war the 11th Battalion was based at Tol Plantation. It conducted daily patrols into the surrounding jungle but had little contact with the Japanese.

After the war the 13th Brigade moved to Rabual, to assist supervising Japanese prisoners. The brigade returned to Australia in January 1946. The 11th disbanded at Puckapunyal in February.