1935 — All states agreed on January 26th.
1974 — National public holiday proclaimed.
Prior to 1935, various states celebrated their own Foundation Day, usually the date their state was gazetted.
Later Australia Day was celebrated on the Saturday closest to the 26th with a Monday or Friday holiday. It was only in ‘94 that the holiday was moved to the actual date.
In 1808 NSW celebrated the 1788 foundation of the permanent settlement on the site of Sydney by Governor Phillip, after nine days at Botany Bay, abandoning that site because of poor soil & a less-sheltered harbour.

I’ve done a lot of research on this, after hearing aboriginal protesters say they were protesting Captain Cook’s “invasion” on that date in 1778.
Wrong date, wrong year, wrong person!
Cook mapped the east coast three years earlier. Sailed into Botany Bay, but didn’t land. He didn’t park the Endeavour on dirt until he holed it on the Barrier Reef off the site of present-day Cooktown. Prior to that he only sent a boat crew ashore occasionally to replenish water.
And 500-odd starving convicts guarded by 200 Marines armed only with muskets hardly constitute an invading army.

They arrived in dribs & drabs between January 17~19th.
Read my post, “Oz Day Fuss”.
