New projections by Statistics Canada suggest the nation's population could reach 63 million by 2073, with the number of people aged 85 or older set to triple.
The agency says migration will be the key driver of population increase under all scenarios, while natural growth only plays a "marginal role" as the population ages and fertility rates remain low.
It says the population will rise from about 40 million in 2023 to a range of 47 million to 87 million over the next half a century, with 63 million being the medium-growth forecast.
The population of people aged 85 and over would increase from 896,600 people in 2023 to between 3.3 million and 4.3 million by 2073.
The agency forecasts the populations of Newfoundland and Labrador, Nova Scotia, New Brunswick, and Quebec to decrease as a proportion of Canada's total population until 2048, under almost all scenarios.
Every scenario meanwhile predicts Saskatchewan, Alberta, and British Columbia to increase their share of the nation's population.