There is generally a lesser bank running along the other side of the ditch which is quite wide but only a few inches high.
The Catrail cuts across the upper Teviot valley, separating the low-lying farmland to the north-east around Hawick in Teviotdale from the hillier up-river country to the south-west.
However, since it is not substantial enough to be an effective military barrier, it seems likely to have been a territorial boundary marker, possibly dating from the Early Middle Ages.
The philosopher, poet and historian John Veitch undertook a survey of the Catrail in the late 19th Century and devoted a chapter to it in his History and Poetry of the Scottish Border, Volume 1 (1893).
He believed that it had been constructed early in 7th Century to mark the south-eastern boundary of the territory held by the Strathclyde Britons.