See the Canmore link in the end-note for a detailed report.
As a scheduled monument, these remains are given legal protection under the Ancient Monuments and Archaeological Areas Act 1979.
My photograph was taken from a point on the bank of the enclosure, at the southern side, and is a view clockwise along its length. The bank leads away from the photographer's position; it is seen most clearly at the centre of the image, from which point it gradually curves away to the right. The lower ground on the left is part of the ditch that surrounds the enclosure.
For an anticlockwise view around the earthen bank, from a point at the north-eastern edge of the enclosure, see NS4884 : Earthworks in Knockinhaglish Wood
The Canmore report states that "one of the channels draining the wood passes close to the S side of the enclosure and impinges upon the ditch" for a length of one hundred feet. That channel is the one mentioned in NS4884 : Knockinhaglish Wood
(which shows a ridge that accompanies that channel).
Early OS maps mark the site as the remains of a church. The name "Knockinhaglish" (sometimes given as "Knockanheglish") probably represents the Gaelic "cnoc na h-eaglais", "knoll of the church". Tradition (whether correctly or not would be difficult to determine) would locate an early church, dedicated to St Kessog, at this site; the place-name may have arisen from that tradition.
In any case, at the time when this photograph was submitted, the 1:50000 OS map labels these remains a "fort", while the 1:25000 map calls them "earthworks".
Finally, it is perhaps worth mentioning, since I have not seen reference to the fact elsewhere, that Roy's Military Survey of Scotland (1747-55) shows what, on the basis of the topography depicted on the map, I take to be the hill on which Knockinhaglish Wood stands. On Roy's map, buildings (or ruins) are indicated in red ink. Two such sites are shown on the hill. The position of the one on the east corresponds fairly well to that of the earthworks, and the name Barachure (which I have not encountered elsewhere) is written beside it.