A witness reports seeing flames and sparks shooting skyward out the back of the house at 60 London St. around midnight on Monday night.
"I was coming home and saw that," she said. "Then right after the firetrucks started arriving."
The witness, who did not wish to be identified, said she saw people come out the front of the house and wondered if everyone was okay.
Four Sault Ste. Marie Fire Services pumper trucks responded to the blaze as well as an ambulance.
It is unknown if anyone was injured or how many people were displaced by the fire.