 Australia's part-time military force, the Citizen Force, was reorganised in 1921 to perpetuate the numerical designations and divisional structure of the AIF.As a result, the 43rd Battalion was re-raised within the 4th Military District in South Australia where it formed part of the 3rd Brigade, headquartered at Keswick Barracks.Upon formation, the battalion drew its personnel mainly from the 2nd Battalion, 43rd Infantry Regiment as well as elements of several other units including the 10th, 48th and 50th Infantry Regiments, which had been formed in 1912 following the establishment of the Universal Training Scheme.