The hospital was designed by Thomas Fulljames using a corridor plan layout.[2] It was built in the Gothic style using local old red sandstone with Bath stone dressings and opened as the Joint Counties' Lunatic Asylum in December 1851.[2] It initially had 210 inmates in 12 wards[3] and was set in grounds of 75 acres of landscaping.[4]
A new infirmary wing was completed in 1861 and a laundry block was added in 1875.[3] The central administration block and the epileptic block were completed in 1883 and the working men's dormitory was opened in 1891.[3] At its peak at the end of the century it had 1,170 patients.[3]
It became the Monmouthshire Asylum in 1897 and was renamed the Monmouth Mental Hospital in 1930[3] before joining the National Health Service as Pen-y-Val Hospital in 1948.[3] After the introduction of Care in the Community in the early 1980s the hospital went into a period of decline and it finally closed in 1997.[3]
Between 1851 and 1950, over 3,000 patients died at the hospital. A memorial plaque for the deceased has now been placed at the site.[5]
The main hospital building was converted into luxury accommodation by Redrow plc under the name "Sarno Square" in 2001.[6][7]