At Ballyfarnoge in County Wexford, a ringfort of roughly forty metres in diameter has left no obvious trace on the surface, yet its circular ditch, or fosse, shows up clearly as a cropmark on aerial photographs. Cropmarks form when buried features such as ditches cause overlying crops to grow differently, taller and greener above the moisture-retaining fill of a ditch, producing a pattern that becomes legible only from altitude.

A ringfort, sometimes called a rath, was the typical farmstead enclosure of early medieval Ireland, used roughly between the fifth and twelfth centuries. A family or small community would have lived within the enclosed area, protected by an earthen bank and accompanying fosse. The Ballyfarnoge example sits on a level landscape, which would have made it a legible and commanding presence in its time, even if only modestly raised above the surrounding fields. An entrance gap on the eastern side is discernible in the aerial record, eastward orientation being fairly common among such enclosures, possibly for practical or ritual reasons associated with the rising sun. The site appears in aerial photographs taken in 2006 alongside earlier photographic records, confirming that the underlying archaeology has persisted despite whatever agricultural activity has since erased its surface expression.