Since the publication of the first six-inch maps in the 1830s, Irish Ordnance Survey maps have been a treasure trove of information, marked by a rich array of descriptive terms and abbreviation. While many are self-explanatory, others - especially those on historical maps - may seem obscure or outdated. This book is your guide to understanding the fascinating terminology found on these maps. From geological and archaeological terms to Irish-language references and obsolete administrative divisions, this comprehensive glossary sheds light on the words and symbols that have shaped our understanding of Ireland's landscape. Also included are: A complete list of abbreviations used on Irish OS maps, A table of map scales and imperial-to-metric conversions, A chart of placename changes and an archaeological timeline for Ireland, Online resources and a curated bibliography for further exploration, As we commemorate 200 years since the establishment of the Ordnance Survey in Ireland, this essential reference offers readers-whether historians, genealogists or map enthusiasts-a deeper appreciation for the artistry and detail behind Ireland's cartographic legacy.