In 1900, antiquarian FitzGerald documented what appeared to be the remains of a square structure with a circular building at its centre, visible only as slight grassy elevations in the landscape. Local tradition held that these earthworks marked the site of a castle, supposedly demolished for its stones, though Ordnance Survey maps placed the actual Colbinstown Castle near the railway station, some 565 metres to the northeast.

The site caught the attention of archaeologists again in the 1960s and 70s when aerial photographs clearly revealed the square-shaped feature that FitzGerald had described decades earlier. These images provided tantalising evidence of something substantial beneath the surface, prompting further investigation when the Cork-Dublin natural gas pipeline was being laid through the area in 1983.

The excavation, however, yielded unexpected results. Rather than uncovering the foundations of the mysterious structure, archaeologists found only three large post-medieval drains beneath a layer of stone rubble that covered the entire 42 by 22 metre cutting. The rubble sat atop undisturbed gravel, with no trace of the buildings that both FitzGerald and the aerial photographs had suggested were there. Whether the earthworks were completely destroyed by agricultural activity, or whether they lie just beyond the excavated area, remains unknown; the square structure visible from above continues to guard its secrets beneath the Kildare soil.