It has no visible walls, no mound, no obvious surface feature. What gives it away is the crop itself: in dry summers, the buried remnants of a fosse, the wide defensive ditch that once defined the enclosure's edge, cause the plants above to grow differently, producing a faint discolouration that only becomes legible from the air.

The enclosure was identified from an aerial photograph taken on 16 July 1971 as part of the Cambridge University Collection of Aerial Photography. Cropmarks of this kind are typically associated with early medieval ringforts or their precursors, settlements in which a circular earthwork defined a domestic or agricultural space. What makes the Annamult example particularly interesting is its context: three other enclosures were visible in the very same photograph, one approximately forty metres to the north, another roughly forty metres to the south, and a third around one hundred and thirty metres to the south-east. The concentration of four such features in close proximity suggests this was not an isolated farmstead but part of a more densely settled early landscape. A field boundary running north to south immediately east of the monument is still upstanding, a rare surviving edge in what is otherwise invisible archaeology.