The woman, in her 20s, was discovered yesterday at a house in Barrow, Cumbria.
A spokeswoman for Cumbria Constabulary said: "Police are currently investigating the circumstances of a sudden death in Barrow.
"The North West Ambulance Service notified the police of a sudden death of a woman, in her 20s, who had been found in a property on Napier Street, Barrow.
"The death is being treated as unexplained and the circumstances are under investigation. Police have arrested a man, aged 68, on suspicious of murder and he is assisting detectives with their inquiries."