The sixth person to die in the UK from coronavirus was being treated by West Herts Hospitals NHS Trust.
The patient, who was in their eighties, had underlying health conditions, and is said to have died at Watford Hospital.
It is believed the virus was contracted in the UK and contact tracing is now underway.
The trust covers the area of St Albans, Hemel Hempstead and Watford.
The Department of Health's Chief Medical Officer, Professor Chris Whitty, said: "I offer my sincere condolences to their friends and family and ask that their privacy is respected.'
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