An oval earthwork, roughly fifteen metres north to south and ten metres east to west, shows up as a cropmark on an aerial photograph taken in 1977. Stand on the ground above it and there is nothing to see. The enclosure has effectively vanished from the surface, leaving behind only that single photographic trace.

Cropmarks form when buried features, walls, ditches, or filled pits, affect how plants grow above them. Crops over a buried ditch tend to grow taller and greener because the disturbed soil retains more moisture; crops over a buried wall grow shorter and paler. From the ground these differences are rarely perceptible, but from the air they can resolve into clear outlines of long-vanished structures. The oval enclosure at Rath More sits within the northern half of a larger ecclesiastical enclosure, the kind of curving boundary that typically surrounded an early Irish monastic or church site. A separate circular enclosure occupies the southern half of the same ecclesiastical boundary, suggesting the site was once a more complex arrangement of spaces than anything visible today would indicate.