The Céide Fields (Irish: Achaidh Chéide, meaning "flat topped hill fields") [2][3] is an archaeological site on the north County Mayo coast in the west of the Republic of Ireland, about 8 kilometres northwest of Ballycastle. The site is the most extensive Neolithic site in the world and contains the oldest known field systems in the world.[4][5] Using various dating methods, it was discovered that the creation and development of the Céide Fields goes back some five and a half thousand years.[6]