Police are appealing for witnesses following an incident in Shildon on Tuesday evening.
Officers were called following a disturbance at an address in Thornhill Gardens just after 5pm.
A man in his 50s has been arrested on suspicion of murder and is currently in police custody.
Detective Chief Inspector Nicola Lawrence, of Durham Constabulary, said: “This is a tragic incident and our thoughts are with the victim’s family at this time.
“I would like to reassure the local community that we are not looking for anybody else in connection with this incident.
“An investigation is now underway and I would encourage anyone with information that might assist our enquiries to get in touch.”
If you have any information call 101 quoting incident reference number 322 of March 30.