Canada is marking its 150th anniversary as a country in towns, cities and at backyard barbecues nationwide.

But the biggest bash is at Parliament Hill in Ottawa, where organisers expect hundreds of thousands of people.

And by mid-morning, they had turned out in their droves - albeit huddled under umbrellas, trying to avoid the rain.

Some partygoers, like 24-year-old students Morgan Haines, Jon Salamati and Nima Sahebi, got to the Hill before the sun had even risen.

Their early morning netted them a prime spot right next to the main stage, where they said planned to stay until after the fireworks at midnight.

The three travelled from Vancouver, on Canada's west coast, to celebrate the day in the capital.

"One-fifty is only going to happen once," Mr Salamati said. "By the time we hit Canada 200, we might not be able to do this trip."

The celebrations include a concert by Canadian artists, a display from Canada's aerobatics squadron the Snowbirds, a citizenship ceremony for new Canadians, and a massive fireworks display.

Canadian theatre giants Cirque du Soleil are performing, as are international acts including U2.

But it was Justin Trudeau, Canada's prime minister, who made the crowds forget the grey skies with a rousing speech celebrating the country's best attributes, delivered in both English and French.

"This is as good a reason as any too reflect on our past, to cheer on today, and to recommit ourselves to the future," he told those gathered in Ottawa.

But he also took a moment to remember Canada's indigenous people, whom he said had been "the victims of oppression" since the first settlers arrived.

"As a society, we must acknowledge past mistakes," he said, telling the audience there was still much work to be done in order to achieve reconciliation.

However, Canada, he said, was determined to see a reconciliation over the coming years and decades.

"It is a choice we make not because of what we did, or who we were, but because of who we are," Mr Trudeau said.

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