Trillick Castle, also known as Mervyn Castle, lies north of the village of Trillick, halfway between the towns of Omagh and Enniskillen, in County Tyrone, in Northern Ireland.
Trillick Castle was built by Captain James Mervyn between 1620 and 1628. The castle was described as one of the best of its kind and was occupied up until the 1800s, being vacant in 1814. It had then passed to General Mervyn Archdale.
Trillick Castle was built as a defended house with a bawn. The site survives as a rectangular block 6.5m wide x 14m long, consisting of the west gable and chimney stack, with fragments of the north, east and south walls of the 2-3 storey defended house. On the ground floor is a large fire place and a bread oven set into the west gable. The first floor had large windows and a fire place.
Trillick Castle was a little hard to find, also because it could not be easily seen from the public road. It is situated on private lands in a small wooded area and can not be visited.