It is between eight and eleven metres wide and barely a metre deep in places, unremarkable to anyone who does not know what they are looking at. This is the remnant of a canal that never quite became one, a waterway that was started, abandoned, and then quietly swallowed by the land around it.

The canal was intended to run for approximately two kilometres along the Shannon's floodplain, skirting shallows in the river itself rather than attempting to navigate them directly. Its course stretched from just below Battle Bridge southward to a point above Inishnagon island in County Leitrim. The work is attributed to Colonel Charles Tarrant, who is believed to have begun construction after 1787, though it was never completed. An undated Longfield map in the National Library of Ireland records it as an "old deserted canal" with an accompanying laneway or towpath, which suggests it had already fallen into disuse by the time the cartographer noted it. The Ordnance Survey six-inch maps, produced from the 1830s onwards, do not mark it at all, though the 1837 edition does indicate its line. By the 1850s, the need it was meant to address had been resolved differently, when the Lough Allen Canal was constructed on the Leitrim side of the river to manage the same stretch of navigation. Tarrant's unfinished channel had been superseded before anyone got around to finishing it.

Almost all of the original two-kilometre length has been filled in over the intervening centuries. What survives, at the northern end, is that 700-metre section, grass-covered and reed-fringed, with no clear trace of the towpath that the Longfield map recorded alongside it. It is the kind of earthwork that registers as a landscape anomaly rather than an obvious historical feature, a long, slightly sunken corridor that only makes sense once you know something dug it out more than two hundred years ago and then left it to settle back into the floodplain.