The construction of Denbigh North Wales Hospital was completed in 1848 and at it's peak had capacity for 1500 patients. It is grade II listed due to it's Victorian asylum style architecture. The hospital was finally closed in 1995 and has lay derelict ever since, slowly decaying away due to natural corrosion and an unfortunate amount of vandalism. There are talks of the site eventually being used for housing and leisure facilities.
More information about Denbigh North Wales Hospital can be found here and here.