Earthwork - but what exactly?

It caught my eye while driving past on a visit to the area—a tree-topped mound outside Portglenone with a slight but distinct dominance over the surrounding landscape. Given its location near the River Bann, long associated with early settlement in Ireland, I assumed it might be a prehistoric hillfort. But it’s not listed on the Atlas of Hillforts of the UK and Ireland. Still, it seemed the site, officially called Knockanhead (the flat-topped hillock), and known locally as Clement’s Hill, had a story to tell.

Historical maps offered bare facts. It was recorded as 102 feet on the Ordnance Survey First Edition (1829–1835), though later editions round it down to 100 feet. PRONI’s historical map viewer however referenced something more intriguing - an entry on the Sites and Monuments Record of Northern Ireland (SMR) describing it as an earthwork and a “possible military encampment”. It was just a hint, but a vivid one.

The SMR draws from the Ordnance Survey Memoirs, which describes the site in Glenone townland on the holding of William Clements as having “a few traces of entrenchments on the south western side. The tradition is that at some former period the site was chosen as fit by some general now forgotten as a fit site for an encampment.” 

The entry explains that the opposing force were stationed on a hill on the other side of the Bann called Knocknabrock. "It seems that after some daylight skirmishing, the party east of the Bann crossed over by night and took the Knockenhead party by surprise and that a deadly combat then ensued in which many of both were slain." A Captain Magill and some others were buried in the "immediate neighbourhood" of the hill.

Human bones have been found in William Clements' garden, the OS Memoirs state, while small cannon and musket balls have been dug up from time to time, including a cannon ball found in 1833 and now in the possession of a Dr Madden of Portglenone. 

The idea of these duelling hills as a battle site resurfaces in the 1927 book On the Shining Bann by R M Sibbett:

"At the western side of Gortfad, touching the Bann between Garvaghy and Bracknamuckley, there is an eminence which resembles a huge sand dune. About half a mile away or less a similar eminence stands in County Derry. These two heights, rising to a hundred and fifty feet or more above the level plain, were at one time scenes of martial activity. Indisputable evidence of this fact survives in arrow heads which have been picked up about the base of both acclivities and over the intervening space...

"If at any time the hillock in Gortfad territory had a name it has long been forgotten; but the eminence corresponding to it in County Derry territory was once known as Knock-an-head and now as Clement's Hill. A sense of loneliness has always attached to the Antrim height, deepened at nightfall by the presence of overshadowing trees. There has been a suggestion, too, of the presence of fairies about the place because of the existence of peculiar thorns and strange effects in the moonlight. In the case of Knock-an-head hill similar remarks also apply."

The military engagement referred to by the OS Memoirs is the April 1689 Battle of Portglenone between the army of King James and the forces supporting his Dutch challenger for the British crown, William of Orange. But reports of arrows and mesolithic flints in the vicinity support the idea that the site has a long history of habitation.

Its military links didn't end in the 17th century either. Another entry in the Site and Monuments Records notes a modern pillbox, likely from the Second World War.

Frustratingly, I haven’t found any evidence of modern archaeological work at Clement's Hill. There’s no LIDAR available either. If you know more—especially about any investigations or oral history—please get in touch.

The clear image above is from Google Maps. Below is my terrible snap when passing in a car (as a back seat passenger gazing through tinted windows - sorry!).