This rectangular earthwork, measuring approximately 60 metres by 45 metres, consists of a raised platform surrounded by a water-filled ditch, or moat. Dating from the 13th or 14th century, it represents the type of defended homestead favoured by Anglo-Norman settlers and prosperous Irish families during the medieval period. The site would have originally supported a timber hall or tower house, along with various outbuildings for livestock and storage, all protected by the encircling moat which served both defensive and drainage purposes.

Today, the site appears as a grass-covered raised area bordered by a depression that still holds water in places, particularly during wetter months. While no structures remain visible above ground, the earthworks themselves are remarkably well-preserved, allowing visitors to clearly trace the outline of the original settlement. The surrounding landscape of gentle farmland has changed little over the centuries, making it easy to understand why medieval settlers chose this location; slightly elevated ground with good drainage and views across the surrounding countryside.

Moated sites like Smithstown are relatively common in south-east Ireland, with over 200 recorded examples in County Kilkenny alone. They represent a fascinating middle ground between the grand stone castles of the nobility and the simple farmsteads of the peasantry, belonging instead to a emerging class of smaller landowners who could afford some defensive measures but not the expense of stone fortifications. Archaeological excavations at similar sites have revealed pottery fragments, iron tools, animal bones, and occasionally coins, painting a picture of self-sufficient communities engaged in mixed farming whilst maintaining connections to wider trade networks through nearby market towns.