Police have confirmed the names of four people who died in a house fire on Williamthorpe Road, North Wingfield.
Emergency services were called to the house at 5am on Wednesday.
Two women, Claire James, 27, and Josie Leighton, 32, were pronounced dead at the scene.
Two boys, aged nine and 12-years-old, were also in the house and were taken to Chesterfield and District Royal Hospital.
Tyler Green, nine, and Jordan Green, 12, were pronounced dead at hospital.
A seven-year-old girl was taken to hospital suffering from minor smoke inhalation. She has since been discharged.
Specially trained officers continue to support family members.
Post mortem examinations will be carried out.
A joint investigation by the police and fire service continues.
Williamthorpe Road has now been reopened.
Anyone with information that could help with the inquiry should contact the police using the non-emergency number 101.