Gartnanoul is a megalithic court tomb located in Killykeen Forest Park, County Cavan, Ireland. Situated near Lought Oughter , the north tomb court is 3 metres in depth and 4 metres in width. Gartnanoul is called a dual-tomb because it has two tombs both in line with each other, with each tomb having its own court. It is estimated that when it was built Gartnanoul would have been 28 metres long, and 8 metres wide. The roof stones are missing although the tomb is in good condition and cairn materials are found scattered around the tomb.