It was raised in 1915 as part of the First Australian Imperial Force for service during World War I and formed part of the 6th Brigade , attached to the 2nd Division .
The 21st Battalion was an infantry battalion of the Australian Army .
21st Battalion was raised in 1915 as part of the First Australian Imperial Force for service during World War I and formed part of the 6th Brigade , attached to the 2nd Division .
The 21st Battalion was an infantry battalion of the Australian Army .