In that time she has made 16 visits to Australia and each trip is remembered fondly by her supporters.
David Flint was 16 years old when Queen Elizabeth II paid her first visit to Australia.
It was 1954 and the recently-crowned Queen, with her husband Prince Phillip, sailed into Sydney Harbour after more than six weeks at sea.
Professor Flint is now the National Convenor of Australians for Constitutional Monarchy and says the public clamoured to meet the Queen.
"There was this enormous feeling of excitement and pleasure across the country. Here was this young, beautiful woman and her handsome consort, coming to Australia. I think the country was absolutely united because there was very strong support for the royal family, particularly during the war. The king had been a symbol of resistance against Hitler and there was this feeling of wonderment that here is the Queen, finally with us."
It was the first time a reigning monarch had set foot on Australian soil, something she may have had in mind as she spoke immediately after arriving at Sydney Harbour.
"Standing at last on Australian soil, on this spot that is the birthplace of the nation, I want to tell you all how happy I am to be amongst you and how much I look forward to my journey through Australia."
The Queen has since visited Australia another 15 times, often tied to important occasions such as opening the Sydney Opera House and the new Parliament House.
For life-long supporters, such as David Flint, Queen Elizabeth's record-setting reign represents a key part of Australia's history and, he hopes, its future.
"She said that my whole life, whether it be long or short, shall be dedicated to your service and the great Imperial family to which we all belong. That key, what she offered and she promised, was service and we see that now."
However Australia's republicans are using the milestone to call for the Queen to be the last non-Australian head of state.
Australian Republic Movement Chairman Peter FitzSimons says the country is ready to step away from Britain's royals.
"We've got people across the political spectrum supporting us. We're not arguing for revolution, we're arguing for evolution. We're saying, the time has come."
But the republic debate continues to divide the public.
"I love the Queen. I don't want some old fella here being in charge!"
"I couldn't care less."
"Me either."
"I realise she isn't running the country, she isn't a governor unfortunately, but I still think her influence is good."
