Manorhamilton Castle is listed by Leitrim County Council as a Protected Structure as follows:
The Castle is a two- or three-storey rectangular house, though most of the third storey does not survive. It is U-shaped in plan, open to the north, with corner towers at four angles. It is surrounded by a bawn, which is a rectangular area defined by a wall (most of which has been rebuilt). There are the remains of lookout towers at the southwest and southeast corners of the bawn wall.
The house itself has internal dimensions of 20m x 8m and the two wings, which are separated from the main house by party walls, have internal dimensions of 7m x 5.25m. There is a courtyard between the two wings but its south wall, which would have had the original doorway, does not survive. There are four corner towers which have between three and five storeys.
Manorhamilton Castle was built by Sir Frederick Hamilton who received a grant of over 5,000 acres in 1621-2. Hamilton had undertaken to build a castle and this was probably not finished until 1636. In January 1642, the castle was besieged by Irish rebels. On January 30th the rebels set fire to the town but failed to capture the castle, and they lifted the siege on April 3rd.
Hamilton left Ireland in 1643-4 and died in Scotland in 1647. The Castle seems to have survived until the Earl of Clanrickard burnt it in 1652. There are a number of local stories about Sir Frederick Hamilton’s escape from the castle.
This fortified house is situated on a low rise on the edge of the town of Manorhamilton This type of Fortified house was constructed in the seventeenth century when artillery had made tower houses redundant. The emphasis in these houses was on light, space and warmth rather than defence, as they tend to include a greater number of large rooms, large windows, large fireplaces and distinctive diamond-shaped chimney stacks. They are very similar in function and design to the plantation houses in Fermanagh.
In compliance with existing legislation in relation to protected structures archaeological surveys were required to be undertaken prior to the commencement of the major restoration works. In 1999 three archaeological surveys were carried out – one on the area external to the bawn walls; another on the area inside the bawn walls and another on the castle building itself.
Trenches were dug and excavations made in the course of this process. Some minor artefacts were uncovered in these digs but none of major archaeological significance.
The restoration work on the Castle and the enhancements to the adjoining Fair Green were then carried out between 2003 and 2009 in co-operation with Leitrim County Council.