Which flag appears in the canton of Australia's national flag?

The flag in the canton of Australia’s national flag is the Union Jack.

The Union Jack occupies the upper hoist-side quarter, or canton, of the Australian flag. It reflects Australia’s historical connection with the United Kingdom and the country’s development as a group of British colonies before federation in 1901.

The rest of the design carries distinctly Australian symbols: the seven-pointed Commonwealth Star represents Australia’s six states and its territories, while five stars depict the Southern Cross. The flag was selected after a public competition following federation, and its first version was flown in 1901.

The Union Jack is sometimes confused with the Australian flag’s other stars because the Southern Cross is also prominent. It is not the Stars and Stripes, the Maple Leaf, or a tricolour. Australia’s flag remained legally and culturally connected to British symbols for decades; the Flags Act 1953 formally established the Australian Blue Ensign as the national flag, with royal assent following in 1954.