The site consists of a raised mound, or motte, which would have once supported a wooden tower, alongside a lower enclosed area known as the bailey where daily activities and additional structures would have been located. This type of fortification was favoured by the Normans as they could be constructed relatively quickly using local labour and materials, making them ideal for establishing control over newly conquered territories.

The motte at Tinnahally rises prominently from the surrounding landscape, its earthen bulk still impressive despite centuries of erosion and agricultural activity. Archaeological evidence suggests the site dates to the late 12th or early 13th century, when Norman lords were consolidating their hold on lands granted to them following the initial invasion of 1169. The strategic placement of the castle allowed its occupants to oversee the surrounding farmland and control movement through the area, whilst the height of the motte provided early warning of any approaching threats.

Today, visitors to Tinnahally can still trace the defensive ditches and banks that once protected the site, though time and farming have softened their original sharp edges. The castle represents one of many similar fortifications scattered across the Irish landscape; silent reminders of a turbulent period when Norman adventurers, Gaelic chiefs, and Anglo-Irish lords vied for control of the island. Though no grand stone walls remain, the earthworks at Tinnahally offer a tangible connection to this formative period in Irish history, when the seeds of centuries of cultural exchange and conflict were first sown.