This substantial earthwork rises four to five metres above the surrounding landscape, measuring 28 metres across at its base and narrowing to about 11 metres at its summit. The mound itself is constructed from compacted earth and stone, creating steep sides that would have made it a formidable defensive position in its day.

The summit features an intriguing arrangement that hints at its medieval origins. A low bank of earth and stone, roughly half a metre high and four metres wide, partially encircles the top of the mound, running from the east-southeast around to the northwest. This defensive bank would have provided additional protection for whoever occupied this elevated position. At the northwest section, where the bank ends, there’s a curious depression measuring 2.5 metres across and 0.3 metres deep; its original purpose remains a mystery to archaeologists.

Unlike many similar medieval fortifications found throughout Ireland, this motte shows no evidence of having been surrounded by a defensive ditch or fosse at its base, nor are there any traces of an associated bailey where everyday activities would have taken place. This absence of typical Norman defensive features makes the Glen motte somewhat unusual and raises questions about its exact function and date. Whether it served as a lookout post, a temporary stronghold, or had some other purpose in medieval Longford remains an open question for historians and archaeologists studying the area’s rich past.