The fire was reported just before 9:45 a.m. at 92 Fern Street in Athol, the state Fire Marshal's Office said.
Authorities have not released the victim's name, but Athol Town Manager Shaun Suhoski said she was a beloved community member and active in her church and neighborhood.
Firefighters believe the blaze began in the kitchen, but they are still investigating the fire's origins.
The two-story home was engulfed in flames and heavy flames when firefighters arrived. About 40 firefighters battled the blaze for an hour before putting it out, the Fire Marshal said.
The Athol Fire Department, Athol Police, and State Police assigned to the offices of the State Fire Marshal are investigating the cause of fire.
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