Police say the victim, who was the only person in the house on The Hill, was pronounced dead at the scene.
The blaze broke out shortly before 12.40am and a joint police and fire investigation has now been launched into the circumstances surrounding the tragedy.
Police closed the road and moved people away from the property for their safety while firefighters from Ashfield, Mansfield, Hucknall and Alfreton tackled the flames.
Det Insp Gayle Hart, of Nottinghamshire Police, said: “Our thoughts are with the woman’s family and friends at this difficult time. An investigation is ongoing to establish the full circumstances and to establish the cause of the fire.
“We are keeping an open mind while we determine what caused the blaze but we are not currently treating the woman’s death as suspicious.”
A file will be prepared for the coroner.
Group manager Andy Macey, of Nottinghamshire Fire and Rescue Service, said: “I would like to share my most sincere condolences with the family and friends of the woman during this difficult time.
“We understand residents living nearby will have concerns about what happened and we will be working to reassure them as best we can in the coming days.
“Our fire investigation team is working with Dexter, the fire dog, and our police colleagues to determine the cause of this fire."