Spanning the Aghakista Stream on two semi-circular arches, it is narrow enough to suggest it was never meant for heavy traffic, and the overgrowth that now softens its stonework only reinforces how quietly it has been left to its own devices.

The bridge's purpose was a functional one: it provided the sole access point into a tuck mill on the far bank. A tuck mill, also known as a fulling mill, was used to finish woven woollen cloth by pounding it in water, a process that thickened and felted the fibres and made the fabric more durable. Such mills were once common features of Irish river valleys, relying on fast-moving water to drive their machinery, and their disappearance from working use has left many of the small bridges and lades that served them looking curiously purposeless. Here at Derrymihin, the bridge outlasts the mill it was built to serve, a modest stone structure that now connects one overgrown bank to another.