What makes this particular site quietly unusual is its traditional name: according to John O'Donovan, writing in the Ordnance Survey Letters, it was known as Brugh Righ, meaning King's Fort or King's Seat. That is a considerable claim for a monument measuring just 25 metres across.

A ringfort, sometimes called a rath, is a type of enclosed farmstead or settlement typical of early medieval Ireland, generally dated to between the 6th and 10th centuries. Most were simply the homes of farming families, their earthen banks providing a boundary as much as a defence. This example at Lotteragh Upper, however, has been classified by archaeologist Seán P. Ó Ríordáin in his 1974 survey as a platform-type ringfort, a variant where the interior is raised or set on a levelled terrace rather than sitting flush with the surrounding ground. The earthwork is defined by a scarped edge roughly 1.6 metres high, an external fosse or ditch just over a metre wide, and a counterscarp bank on the far side of the ditch that rises to nearly 2.6 metres internally. The ground then drops sharply away towards the river to the north and west, making that natural fall part of the site's overall defensive logic. T.J. Westropp documented the earthwork in detail in 1916 to 1917, and his plans remain a reference point for the site's layout. About 150 metres to the north-west sits a companion ringfort, and the two are known locally as the Raheens, a name Mainchin Seoighe traced in his 2000 study to the Irish Raithini, simply meaning little forts.

A public road skirts the south-eastern to south-western edge of the bank, making the monument reasonably easy to locate, and an unpaved pathway crosses the fosse on the north-western to north-eastern side. The interior slopes gently downward to the north but is largely inaccessible due to thick vegetation. Visitors coming to look rather than enter will find the earthwork's profile clearest from the road side, where the relationship between the fosse and the counterscarp bank is most legible. The riverside situation, with the ground falling away steeply towards the Maigue, gives a clearer sense than most such sites of how topography and earthwork were used together.