[1] Following Federation, in 1913 Cockatoo became the Commonwealth Dockyard, and the island, both through ship-building and servicing, played an important role both in the development of the Royal Australian Navy and during the First World War.

From 1933 the dockyard was leased from the Australian Government by the Cockatoo Docks & Engineering Company and the island played a very significant role during the Second World War.

[1] Due to the uncertain grain supplies available in the early colony of NSW, Governor Gipps in 1839 decided to embark on a silo construction program on Cockatoo Island.

Gipps hoped to increase storage up to 100,000 bushels if the low price of wheat then prevailing continued.

The other major group of convict-constructed underground silos are located on Norfolk Island, but these are cut into the earth.

[1] Criterion A: Processes Excavated during 1839-40, the grain silos are historically highly significant for their direct association with the convict era in New South Wales.

Further, the silos reflect aspects of food supply and government administration in the early years of the colony.

[1] Criterion F: Technical achievement The silos are finely excavated and reflect a high degree of stonemasonry skills on the part of their builders.

[1] This Wikipedia article was originally based on Underground Grain Silos, entry number 105264 in the Australian Heritage Database published by the Commonwealth of Australia 2018 under CC-BY 4.0 licence, accessed on 16 September 2018.