A complete tower, in good condition, built externally of coursed sandstone ashlar, with some limestone internally. The external diameter at the base of the tower is 4.82 m, and 4.14 m at the level of the top windows. Romanesque sculpture is found on the doorway and cornice. The seven windows of the tower are all dressed but none have sculpture.

The tower was restored in 1835 by Eniskillen architect Robert Rexter.

A drawing by John Frith in 1808 shows the tower with an elder tree growing from the roof. In 1834 the tree was blown down taking part of the roof with it. O' Donovan, who visited the site while the top of the tower was still breached, described the south side of the cap as 'thrown down', and the S window as 'considerably injured'. In May 1844, the interior was excavated by local antiquary, Edmund Getty. There were no traces of burials. In 1896 the Board of Works, who made detailed measurements of the structure, carried out repairs on the tower. In 1971 further work was carried out on the tower by the DOENI who removed an earlier wooden spiral staircase, and inserted wooden floors.

St Laseren, or Molaise (d.563/570) founded the early monastery. Between 563 and 1168 the Annals record the death of twenty abbots as well as a number of incidents including, in 863, the destruction of all of the churches of Lough Erne including Devenish. In 1157 the Annals of Ulster record that 'Daimhinis and all its churches were burned' (131). In 1176 the Annals record that 'Domhnall, son of Mhlaoibh O Maoil Ruanaidh, king of Fir Mhanach, was burned by his own kinsmen in the round tower of Daimhinis'. (Miscellaneous Irish Annals, 59)

The discovery in 1972-3 of the foundations of a second round tower at Devenish has led to the suggestion that the standing tower may have replaced one damaged by the 1176 fire (Hamlin). There is no other known example of a cornice in this position on a round tower.