No earthworks, no raised rim, no dip in the ground. The ringfort it refers to has been completely levelled, absorbed into the surrounding pasture, and exists now only in memory, in a name, and in a nineteenth-century map.

A ringfort, or rath, is an early medieval enclosed settlement, typically consisting of one or more earthen banks and ditches encircling a domestic space. They were built and occupied roughly between the fifth and twelfth centuries and are among the most common archaeological monument types in Ireland, though that commonness has not always saved them. The Smithfield example, which measured approximately thirty-five metres in diameter, was recorded on the Ordnance Survey six-inch map of 1842, depicted in the characteristic hachured style used to indicate circular earthworks. It sat on a gentle north-east-facing slope with an extensive view northward across the Blackwater River valley, a position typical of ringforts, whose builders generally favoured elevated ground with long sightlines. By the time W. Bowman noted it in 1934, in a published account that placed it on land belonging to a J. D. Ryan, it was already recorded alongside a companion site nearby, CO032-08802-, a second single-ramparted ringfort on the same holding that had also been levelled.

What remains is the field name, which turns out to be a remarkably durable form of folk memory. Across Ireland, names like "fort field", "fairy fort", or simply "the fort" have preserved the location of monuments that the landscape itself no longer shows. In this case, the 1842 map and Bowman's 1934 record together allow the site to be pinned down with reasonable confidence, even if a visitor standing in that pasture above the Blackwater would have no way of knowing, from the ground alone, that anything was ever there.