The enclosure at Beeverstown measures roughly 56 metres on its longer axis and 44 metres across, its outline formed by a combination of scarps and banks depending on which side you approach. A scarp is simply a slope cut into or built up from the ground surface, and here the southwestern and part of the northwestern sides are defined by one, while a more substantial bank, rising about 0.75 metres above the interior, defines the southeastern edge. Around much of the perimeter runs a fosse, the older term for a ditch dug to reinforce an enclosure's boundary, and the fosse here is notably uneven in its depth and character, shallow on some sides and considerably more pronounced on the southeast, where it reaches a depth of over a metre and a width of more than six metres.

One of the more curious features is what happens at the northern corner, where the fosse broadens and opens into a pond. The southeastern ditch also extends beyond the enclosure itself in both directions, which has led to the suggestion that it may originally have served a drainage function as much as a defensive or territorial one. The land around Beeverstown was poorly drained before forestry was planted to the north and northwest, and water management may well have shaped the monument's form as much as any concern with enclosure. Inside, the ground is level and raised slightly above the surrounding field, more noticeably so on the southeastern side where the difference reaches around 0.4 metres. A further detail complicates the picture: the ghost of a levelled linear bank, running roughly east to west for about 50 metres, crosses the interior off-centre to the south and continues westward beyond the enclosure, hinting at internal subdivision or an earlier or later phase of activity. By the time the Ordnance Survey mapped the area for its second edition in 1906, there were buildings shown immediately to the northwest of the monument, but no trace of these survives above ground today.