Denise Ann Williams is believed to have been hiking in Cape Breton Highlands National Park, in the province of Nova Scotia on the country's south east coast, when she disappeared.
The 62-year-old was last heard from on April 15 when she indicated she was travelling to the town of Cheticamp nearby the park.
Authorities were alerted on Tuesday local time that Ms Williams was believed to be missing in the park, sparking a major search effort.
Her rental vehicle, a Nissan Sentra, was located at the Parks Canada Visitor Centre near the beginning of the Acadian Trail, which has a "moderate" difficultly rating.
The park in known for its rugged and steep coastline and is home to wildlife including moose and black bears.
Conditions in the area have been fluctuating between around zero to 10 degrees, with strong winds and snow expected in the coming days.
The Royal Canadian Mounted Police are spearheading the search along with other agencies including specialised air and ground search teams.
Ms Williams was described as 162cm with greyish blonde, shoulder-length hair.
She is believed to have been wearing a dark winter jacket, a powder blue beanie with "Antarctica" written on it, an orange and blue scarf, and glasses.
The Department of Foreign Affairs and Trade confirmed it is providing consular assistance to Ms Williams' family.
"Owing to our privacy obligations we are unable to provide further comment," a department spokesperson said.
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