Founded around 1660 by Sir Charles Coote, this fortified house was likely built on the site of one of two earlier castles mentioned in the 1657 Down Survey. The main house was abandoned shortly after 1789, becoming the atmospheric ruin visible today, whilst a new Rush Hall House was constructed just 10 metres to the south.

What makes this site particularly fascinating is its elaborate defensive system of bawn walls and flanking towers, which appears to have originally consisted of three separate fortified areas. The most impressive surviving section is the eastern bawn, a square enclosure measuring roughly 65 metres on each side, with limestone walls standing up to 3.7 metres high. At the corners, pentagonal flanking towers bristle with gun loops; ten per tower, each consisting of a vertical slit with a central hole for the gun barrel, set into square embrasures. These distinctive five-sided towers bear a striking resemblance to those at the plantation fort in Monaghan, built around 1611, suggesting Rush Hall Court was designed with serious defensive capabilities in mind.

Archaeological evidence points to a more complex fortification than what survives today. The western bawn wall extends 14 metres beyond its southern counterpart, with remnants of a flanking tower at the southwest angle, indicating a second bawn area once existed south of the main enclosure. A third bawn area to the north and northwest of the house survived until the late 1970s, when its walls were demolished to make way for farm buildings. The surviving eastern bawn, with its cobbled surface now converted to lawn, once served as an orchard after its defensive purpose became obsolete. Today, visitors can still trace the original entrances, examine the well-preserved gun loops, and even spot the threshold stone in the northeast tower, offering a tangible connection to this remarkable example of seventeenth-century fortified domestic architecture.