Secret tunnels were discovered beneath the grounds and the ruins of the historic Marblehill House in County Galway, Ireland in the 1990s. The passages seem to date back to the late 17th and early 18th centuries and the hypothesis is that they originally formed a network to manage water. The tunnels are formed out of thick-cut stone slabs, based on the style preferred for the old estate house and surrounding building’s structure, they were erected at the same time as the house and outbuildings down the small boreen adjacent to the ruins of the estate house. The long tunnels are just about large enough for someone to crawl into because that was the only way how any blockages would have been removed during these times.
After discovering the tunnels it was decided to try and find out the purpose of them. Firstly, “to attempt to confirm this is, in fact, what the tunnels were for”.
“Secondly, to find what the condition of the tunnels was and also to see if the long tunnel network extends under other parts of the buildings and grounds.
“Unfortunately the tunnels are too small and remain deliberately hidden to allow any public access.”
Initial exploration started in the 1990s and again more recently. The tunnels go underneath local fields and underneath the ruins of Marblehill House as well as branching off underneath the courtyard behind the ruins.
Damage to Marblehill Buildings
Recently the tunnels were checked for any damage caused by heavy plant machinery that was used under the direction of a bankrupt property developer who fairly recently brought a small part of the old estate, hoping to later capitalise on the ruins. The original cobbled courtyard was ripped up and destroyed as were some outbuildings and arches that were damaged by bulldozers and diggers in 2020, but miraculously on inspection, the tunnels remained intact and still hidden and now completely overgrown.
Only one person is now known to know where the exact location of the tunnel entrance is, which was deliberately sealed up again to preserve and protect it.
Marblehill Magazine thanks and credits the person who shall remain anonymous for the sake of historic preservation, that gave us this information and old tunnel photographs.