Lime kilns were stone-built furnaces used to burn limestone at high temperatures, reducing it to quicklime, which farmers then spread across acidic fields to improve soil fertility. They were also used in the production of whitewash and mortar, making them essential to both agriculture and building. Thousands were constructed across Ireland from the seventeenth century onwards, yet most have gone unrecorded, crumbling back into the hedgerows and field margins where they were built.