Devenish or Devinish  (from the Irish: Daimhinis , which means “ox island”) is an island in Lower Lough Erne, County Fermanagh, Northern Ireland. Oriented roughly north-south, it is about one and a quarter miles long and two-thirds of a mil wide. The most important place to take the ferry to the island is Trory Point, just outside Enniskillen. Devenish Island owned by Kilravock Christian Trust. 
Devenish contains one of the finest monastic sites in Northern Ireland. A round tower is believed to be from the twelfth century on the island, as the walls of the Oratory of Saint Molaise who established the monastery in the 6th century,  on a pilgrim route to Croagh Patrick in County Mayo. It became a center of scholarship and also raided by Vikings in 837 and burned in 1157, that later flourished as the site of the Parish Church and St Mary’s Priory in August.
There’s extensive low earthworks on the slope, but the earliest buildings are St. Molaise house (a very small church) and the fine round tower close, both with good Romanesque decoration of the 12th century. The round tower is about 30 meters (100 feet) long and can be climbed using internal ladders. It has a sculpted Romanesque cornice heads and ornaments during the conical stone roof.  Nearby is a cross carved with spiral patterns and human heads.There are also several cross-plates, one with an interlaced design and a medieval carved cross. Near the round tower, the foundations of another tower found that the current tower probably been replaced. 
The smallest of the three churches (Mo Laisse house, named after the founder of the monastery) is from the late 12th or early 13th century. It has smalantae with bases carved with classical motifs. Only the lower portions of the walls and some of the roofstones survive. 
Team Pull Mor , the lower church, dates from the early 13th century with a beautiful molded south window. It was extended to the East in about 1300, and later additions include a residential wing in the north and Maguire chapel in the south, with the 17th century heraldic plates.
On the hill sits St Mary’s Priory in August which is the middle of the 15th century and early 16th century, the church tower and small north cloister.Priory has an intricately carved mid-15th century high cross in the cemetery.
There are several hundred resolve architectural fragments on the site, and among those over 40 stones from an otherwise lost, richly decorated Romanesque church. Some of the many loose stones are displayed and which, in its historical context in the small visitor center.
Abbey ruins including churches, round tower, etc. are State Care Historic Monument in the townland of Devenish, Fermanagh City Council area at grid ref: area of H224 469.  The monastic site (the area around the state health monuments, grid ref: H224 469) and Rath (grid ref: H2215 4768) is scheduled historic monument. 
- List of archaeological sites in County Fermanagh
- Northern Ireland Environment Agency
- List of townlands in County Fermanagh
- Ó Khln Krkrán
- The Round O
- Jump up ^ placental Database of Ireland: Devinish
- Jump up ^ http://www.kilravockcastle.com/
- ^ Jump up to: abc . O’Neill, B (eds) (2002) Irish cathedrals, churches and monasteries. London: Caxton Editions. p. 63rd
- ^ Jump up to: ab Weir, A (1980). Early Ireland. A Field Guide. Belfast Blackstaff Press. p. 144. ISBN 0-85640-212-5.
- Jump up ^ “State Care of historical monuments” (PDF). Environment and Heritage Service. March 2007. Retrieved December 3, 2007.
- Jump up ^ “Scheduled historical monuments” (PDF). Environment and Heritage Service. March 2007. Archived from the original (PDF) of 5 November 2008. Retrieved December 3, 2007.
- Curtis, Liz (2004). “Ancient Island places on Lough Erne”. Culture Northern Ireland. Retrieved 19 March 2009.
- “Devenish Island”. www.enniskillen.com. Retrieved 19 March 2009.
- “Devenish Monastic Site”. Northern Ireland Environment Agency.Retrieved 19 March 2009.