It is an icehouse, a type of cold-storage vault once found on most sizeable Anglo-Irish estates, typically built into a bank or hollow and packed each winter with ice cut from nearby ponds or rivers. The ice would be layered with straw or sawdust and could last well into summer, supplying the kitchens of the big house with refrigeration long before electricity made the whole business obsolete. What makes the Shannongrove example quietly compelling is its setting: rather than being tucked into a hillside as icehouses often were, this one sits in level pasture, surrounded by standing water deep enough to have defeated the surveyor who came to record it.

The site sits within the broader demesne of Shannongrove House, recorded in the Historic Environment Viewer under reference LI003-028. The record was compiled by Denis Power and uploaded in August 2012, by which point the mound was already so heavily overgrown that its full dimensions and condition could not be properly assessed. The water surrounding it had made access impossible on that visit, leaving the structure something of an open question. Icehouses were generally built with a domed or vaulted chamber below ground, with thick earthen or masonry walls to maintain low temperatures, and many Irish estate examples date from the eighteenth or early nineteenth century, though the Shannongrove notes do not specify a construction date.

For anyone with a particular interest in estate archaeology, the site is on private land within the Shannongrove demesne, and conditions on the ground are likely to remain awkward. The surrounding water is not incidental; it is part of what has preserved the mound from disturbance while also making it genuinely difficult to reach. The vegetation overgrowth noted in 2012 will almost certainly have thickened since. Visiting during drier summer months might improve conditions marginally, though the waterlogged nature of the pasture suggests this part of the demesne holds water regardless of season. The mound itself, glimpsed from a distance through scrub and rushes, gives little away about what lies beneath.