Glenconkeyne (from Irish Gleann Con Cadhain, meaning 'valley of Cadhan's hound') is an ancient Irish district in what is now southern County Londonderry, Northern Ireland. Glenconkeyne formed the western portion of the former barony of Loughinsholin, with the ancient districts of Clandonnell, Killetra, and Tomlagh comprising the rest. The area Glenconkeyne covered corresponds to the present-day parishes of Ballynascreen, Desertmartin, and Kilcronaghan.
Glenconkeyne has also been recorded in historical sources as Glankonkein and Glanconkeyne.
As a result of the dense forest that used to cover Glenconkeyne and Killetra, both formed the most inaccessible part of the whole of Ulster. The Clandeboye O'Neills are recorded as descending from the thick forests of Glenconkeyne from where they would conquer the shattered remnants of the Earldom of Ulster, becoming the principle Gaelic lords of eastern Ulster, with their territory known in English as Clandeboye.
Local legends allegedly state that Glenconkeyne was a gift of Brian Carrach O'Neill to Cadhan O'Henry for defeating a monstrous hound that was terrorising the region, however the scholar John O'Donovan states that across the country many things appeared to be attributed to an areas last lord, as Brian Carrach O'Neill in this case was. Brian Carrach O'Neill would build a residence near the border of the parishes of Kilcronaghan and Ballynascreen, which became known as Dún Tí Bhriain, preserved as the name of the modern townland of Duntibryan.
In the closing stages of Tyrone's Rebellion, Hugh O'Neill, Earl of Tyrone and his supporters withdrew into the Glenconkeyne Woods following the Burning of Dungannon. Tyrone was able to successfully evade capture until he made peace with the Crown.