Stretching roughly 84 metres along the upper foreshore in a NNE-SSW orientation, this post alignment crosses a creek in a manner characteristic of post-medieval fish weirs, structures built by driving rows of stakes into tidal flats and connecting them with woven wattle panels to create a funnel or barrier that would strand fish as the water receded.

Recorded by Aidan O'Sullivan in July 2000 and published in 2001, the structure includes a secondary element a short distance to the northeast: a post-and-wattle fence, just 6 metres long and oriented roughly north to south, preserved in the estuarine clays. Post-and-wattle construction involves weaving flexible branches or rods between upright stakes, a technique with a very long history in Ireland and one that survives well in waterlogged, anaerobic conditions like those found in tidal mudflats. O'Sullivan noted that this fence may form part of the same weir system, perhaps serving as a wing or partial barrier to direct fish into the main alignment.