Coordinates: 54°18′18″N 9°27′25″W / 54.305°N 9.45694°W / 54.305; -9.45694 (Céide Fields)

The Céide Fields (Irish: Achaidh Chéide, meaning "fields of the flat-topped hill") is an archaeological site on the north Mayo coast in the west of Ireland, about 8 kilometres northwest of Ballycastle. The site is the most extensive Stone Age site in the world and contains the oldest known field systems in the world. 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.

The discovery of the Céide Fields originally began in the 1930s when a local man, schoolteacher Patrick Caulfield, noticed piles of stones which were uncovered as he cut away turf for fuel. In these piles he saw a design that could not have been haphazard; Caulfield noted that the stones must have been placed there by people, because their configuration was clearly unnatural and deliberate. Furthermore, the stones were positioned below the bog, which meant they were there before the bog developed, implying a very ancient origin.