It stands roughly two metres high at the front elevation, and at its base are two low lintelled passages, each barely sixty centimetres tall and forty centimetres wide, through which a person could not comfortably pass. These were not doorways in any conventional sense. They are the draw holes of a lime kiln, the openings through which spent ash and burnt lime were raked out after firing.

A lime kiln is essentially a stone-lined furnace used to convert limestone or shell into quicklime by burning it at high temperature. The resulting material was mixed with water to produce slaked lime, which served as mortar, whitewash, and, crucially for agricultural communities, a soil conditioner spread across acidic land to improve crop yields. The Shanacrane kiln follows a form common across rural Ireland: a rectangular stone-lined funnel, here measuring roughly 2.73 metres by 1.78 metres with rounded corners, into which alternating layers of fuel and limestone were loaded from the top. The two lintelled passages at the base allowed air to feed the fire from below and gave access for clearing the kiln once a burn was complete. This particular structure is described as disused and roadside, suggesting it served a local farming community and was positioned for ease of access when carting in raw stone and carrying out the finished lime.