That collision of the very old and the relatively recent is, in its quiet way, what makes the site worth pausing over. The enclosure measures roughly thirty metres in diameter, and what little survives of it is fragmentary enough that most people walking this ground would see nothing of interest at all.

The site appears on the Ordnance Survey six-inch maps as a roughly circular, tree-planted enclosure, the kind of feature that surveyors in the nineteenth century were careful to record even when the ground-level evidence was already faint. Enclosures of this type are generally understood to be early medieval in origin, the remains of a ringfort or similar enclosed settlement, though the Castlegar example is too poorly preserved to say much with confidence about its original character or use. To the east of the dividing field wall, the enclosure boundary survives as a low scarp, a slight drop in the ground that hints at a former bank or ditch. To the west, a curving line of vegetation may follow the line of a fosse, which is simply a defensive ditch dug around the perimeter of such an enclosure. The trees that once grew inside have since been cleared. Notably, another monument of similar type lies approximately eighty metres to the north, suggesting that this part of Castlegar was once a more active and layered landscape than its present appearance would suggest.