The 13 acre Fedw Hir site, between Aberdare and Mrthyr Tydfil, is on the market with Colliers International with a guide price of £500,000.
The site includes a variety of buildings and offers any number of alternative uses subject to planning permission.
Amy Brooksbank from Colliers International said the well-known site, sited within a half mile of the Heads of the Valley Road, had a colourful history.
She said: “The majority of the buildings on site date from around the 1920s and 1930s. The Groundwork Merthyr & Rhondda Cynon Taff charity acquired the site for its new office base in the 1990s. Prior to that it had been used as a smallpox hospital, a residential school for children with diseases, housing for American soldiers during the Second World War and more recently a respite hospital.
“Over the last five years the trust has been developing the site as a showcase for conservation, pre-employment training and volunteering”.
Amy went on: “The site includes a diverse range of buildings, including a visitor centre, offices, a house, storage barns and extensive workshops, and has several acres of open meadowland and woodland complete with a stream and small lake”.
“Potential alternative uses for the site could include hotel, bed and breakfast, leisure, offices, equestrian centre or residential subject to the usual permissions.”