The area had attracted scrutiny from Dúchas The Heritage Service largely because of the concentration of shipwrecks recorded in its waters, so it was maritime archaeology that brought investigators to the site; what they found instead lay underfoot.

The first mound presented itself as a spread of charcoal-rich black soil and red sandstone, measuring roughly 25 metres by 12 metres. Immediately to its north-east, and running at right angles to it, a second possible mound was partially exposed during topsoil-stripping, though because only a portion of it came to light it remains unclear whether it forms a distinct feature or is connected to the main one. Both were subject to small-scale testing and sampled for dating purposes. Their character, particularly the charcoal-rich matrix of the larger example, raises the possibility of prehistoric activity at the site, and the findings fed into Michael Connolly's doctoral research on prehistoric settlement in the Lee Valley area of Kerry, completed at University College Cork in 2008. Once the limited investigation was concluded, neither mound was disturbed further; both were covered with geotextile matting and reinstated beneath the ground surface, leaving Blennerville Port looking much as it did before the diggers moved in.