The ACT has led the nation in voting to legalise same-sex marriage, returning 74 per cent support for changing the law.
Results published by the Australian Bureau of Statistics showed 26.0 per cent of Canberrans voted against changes to allow same-sex couples to marry, with the capital recording a participation rate of 82.4 per cent.
Nationally the response rate was 79.5 per cent, returning overall support of 61.6 per cent for changing the law. Nationally 38.4 per cent voted "no", representing 4.9 million people.
The results show 175,459 Canberrans voted "yes" and 61,520 voted "no".
Women were more likely to participate in the non-compulsory survey than men. In the ACT, 84.6 per cent of eligible women and 80.1 per cent of eligible men took part.
In the ACT, those aged 70 to 74 were the most likely to respond to the survey - 90.9 per cent of the age group participated.
The participation rate was lowest in the 20 to 24 years age group, at 77.5 per cent.
Voters across the Canberra region supported changing the law.
In the electorate of Eden-Monaro, which surrounds the ACT, 64.9 per cent of voters supported same-sex marriage, while 35.1 per cent were opposed.
In the NSW south coast electorate of Gilmore, 62.0 per cent of voters supported same-sex marriage, while 38 per cent were opposed.
In every state and territory, the over 70s returned surveys in the highest numbers, with participation lower among younger people – a result in line with critics who said a postal survey would favour generations still familiar with posting letters.
The ACT had the highest proportion of over 70s responding, with 91 per cent of people in the age group returning their surveys.
In other states, excluding the Northern Territory, between 89 and 90 per cent of over 70s responded.
In the ACT, the lowest participation rate was among people aged 20 to 24, of whom 77.5 per cent returned survey forms.
Other states also recorded lower participation rates among younger generations - in NSW and Victoria the lowest proportion of returned surveys was among people aged 30 to 34.
ACT Chief Minister Andrew Barr said the results showed federal Parliament must act quickly to legislate for same-sex marriage.
"We had the highest yes vote of any jurisdiction, demonstrating how inclusive Canberrans are," he said.
"Marriage equality is about the values we hold dear. All Australians should be treated equally under the law — and that includes being able to marry the person they love."
Canberra MP Gai Brodtmann paid tribute to same-sex couples and their supporters.
"We know Canberra is an inclusive and progressive community and today's vote of 74 per cent in favour of marriage equality underscores this.
"Today is a day of celebration for LGBTIQ Australians, and for all Australians who believe in fairness and equality.
"I congratulate the LGBTIQ community and their families for their commitment and persistence over many years, and through the course of this survey, which has been challenging."
Senator Zed Seselja, among the leading opponents of same-sex marriage within the Turnbull government, said he'd work to secure religious protections.
"I voted no and whilst I am naturally disappointed in the result, I respect the decision of the Australian people.
"I will now work to ensure the result is reflected in the Parliament and the appropriate safeguards are put in place to protect freedom of speech, freedom of religion and parental rights."
ACT Greens leader Shane Rattenbury said the people of Canberra had spoken up for equality and human rights.
"This unnecessary and divisive postal survey has stimulated robust debate on the private lives of people who simply want the right to marry the person they love," he said.
"The people have spoken. It's time to end marriage discrimination – it's a common sense, human response, and reflects our community's values."
Here's how Australia voted:
Yes: 61.6 per cent or 7.8 million people
No: 38.4 per cent or 4.9 million people
A relationship banned under traditional law.
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