The mound itself was never a tidy monument. Records describe it as irregular in shape, roughly 23 metres in diameter but only about seven centimetres high, its surface pocked with depressions. Easy to overlook, easy to misread, which may explain why the earliest cartographic record, the Ordnance Survey six-inch map of 1837, labelled it simply as a fort. It took another century before anyone noted what it actually contained.

The National Museum carried out an excavation in 1934, uncovering skeletons and a single iron stirrup, found just below the surface at a depth of around sixteen centimetres beneath the sod. The stirrup, a relatively datable object, pointed toward medieval activity, though the mound's full story proved harder to resolve. When Dublin Corporation moved in during the 1960s to landscape the area, approximately twelve more skeletons came to light across two distinct levels within the mound, suggesting it had been used for burial on more than one occasion. Neither phase of burial left any obvious trace of structure or grave slabs, which makes formal interpretation difficult. The site does not fit neatly into the usual categories of early Christian cemetery or organised medieval burial ground. By the time researchers such as Cahill and Sikora examined the record in 2011, the mound had been gone for decades, its documentation drawn largely from the 1934 dig and the observations made during the Corporation's 1964 earthworks.

There is nothing to see at ground level today. The site sits within what became built-up suburban north Dublin, absorbed by twentieth-century development in much the same way as many low-lying earthworks across the county. For anyone tracing the archaeological landscape of the Finglas and Coolock fringe, the Bonnybrook mound serves as a reminder of how thoroughly the record can be closed off, first by a misidentification on a nineteenth-century map, then by a landscaping scheme, and finally by the simple fact that absence leaves no marker. The OS 1937-8 edition, which corrected the earlier label to "site of burials," at least got the last word in print before the ground was cleared.