Straya DayThe unofficial history of Australia's national day since the first contentious one, thereby offering 237 other reasons for a day off. Like it or not, 26 January in Australia has become a significant day of both celebration and mourning. Most countries, if not all, have a national day. The reasons to celebrate a national day include independence from a colonial power, the signing of a treaty, or an act by a monarch, political leader, or patron saint.