Treanmor is a neolithic cairn, most likely an unopened passage-grave, on the summit of the north end of rhe ridge of Treanmor in the Bricklieve Mountains in County Sligo. It is located just east and under the shadow of Kesh Corran Mountain. To the east is the large Carrowkeel Megalithic complex, while to the north is the ruined passage-grave on the spur of Carnanweelan The cairn at Treanmor is unopened and appears to be fairly undisturbed. It is a low mound of locally quarried limestone, about 15 meters in diameter, 240 meters up on a long limestone spur.
Treanmor is one of a group of hills consisting of Treanmacmurtagh, Threen, Sheecor and Cairnaweeleen, each with a neolithic cairn on the summit. In the local landscape mythology these hills are called the piglets of the great sow Cail Céis, who was slaughtered here by warriors from Newgrange. The huge body of Cail Céis became the Mountain of Kesh Corran. With Kesh on the west and Carrowkeel on the west, the views from these four hills are directed to the north and south.
There are several monuments on the hill of Treanmor: a ringfort, a cashel, possible enclosure, and a few relatively modern house ruins. The view from this site, as shown above, is quite spectacular on a clear day.
In boggy pasture, on the summit of a flat-topped ridge, built onto the north-facing slope. A cairn (13 mmeters x 14 meters; maximum height 1.5 5meters) of medium to large limestone stones, circular at the base and rising to form a bowl-shaped profile; the sides are mostly sod-covered and the top has been dug into.
An enclosure (SL040-011) lies some 60 meters to south.
On top of a narrow plateau, surrounded by bog and karst. An irregular grass-covered hollow (interior dimeters 50.5 meters north to south; 67 meters east to west) enclosed on the north side by a straight stretch of stone wall (Top 1.2 meters; height 0.6 meters; external height 0.5 meters) and elsewhere by a curving irregular wall of large limestone slabs and boulders (Top 1.3 meters; interior height 0.7 meters; exterior 0.4 meters). The straight north wall extends c. 80 meters eastwards from the enclosure across the plateau, turns at right angles to south and joins north edge of a cashel (SL040-012001). A cairn (SL040-010) lies c. 60 meters to the north.
There is another small flat cairn, possibly a tertre, an early form of passage-grave, on Kelly's hill, the smallest of the hills around Lough na Leibe.
In rough pasture, on the narrow summit of a ridge and within the north end of a field system (SL040-063001-). A grass-covered oval flat-topped cairn (10.1 meters x 9.7 meters; height 1.2 meters). Remains of an external revetment, with five stones still in situ, are evident at north-east. There is a hollow (diameter 1.5 meters) in the centre of the top. A low stone field boundary extends to east and west from the cairn. A hut site (SL040-065----) lies 17 meters to north.