The fire, which is about 30 kilometres (19 miles) west of downtown Halifax, has already forced 18,000 people to evacuate their homes.
No fatalities have been reported but about 200 homes, structures have been damaged, the CBC reported, citing the Halifax Regional Municipality.
Forest fires also led to evacuations of about 400 homes in the province of New Brunswick over the weekend, officials said.
"The stories and the images we're seeing coming out of Nova Scotia and New Brunswick are heartbreaking," Prime Minister Justin Trudeau told reporters in Ottawa, pledging federal support for the Atlantic provinces.
The Halifax wildfire was expected to cause poor air quality hundreds of miles to the south in parts of the U.S. East Coast and Midwest as smoke drifts across the regions.
Persons:
David Steeves, Justin Trudeau, what's, Brendan O'Brien, Ismail Shakil, Sriraj Kalluvila, Marguerita Choy, Deepa Babington
Organizations:
HALIFAX, U.S, Nova, Nova Scotia Department of Natural Resources, CBC, CBC News, U.S ., National Weather Service, Thomson
Locations:
Nova Scotia, Halifax, Canadian, Halifax Regional Municipality, New Brunswick, Ottawa, Atlantic, Bedford , Nova Scotia, West Bedford, Alberta, U.S . East Coast, Midwest, Michigan, Ohio, Pennsylvania , New Jersey, New York, Philadelphia, Chicago