This impressive circular earthwork, which once enclosed a sixteenth-century Fitzpatrick castle, dominates the landscape despite the castle itself having long since vanished. The castle, built from distinctive red brick that gave the site its name, stood within this ancient fortification until it was reduced to ruins sometime before the 19th century. Early Ordnance Survey maps from the 1800s show the castle as a north-south aligned building in the southeast quadrant of the fort, complete with what appears to have been an L-shaped bawn wall forming a defensive enclosure around the structure.

Local tradition adds colour to the site's history, claiming that a laneway called Cromwell's Road once approached the castle, supposedly marking the route Oliver Cromwell took when marching from Portlaoise to Birr during his Irish campaign. Though no stonework from the castle remains above ground today, archaeological testing in 2002 and 2003 revealed various features including pits and linear ditches in the vicinity, whilst aerial photographs still show the ghostly outline of the levelled walls. A 40-foot-deep stone-lined well, which once served the castle, was located behind where the building stood, and fragments of red brick can still be found just beneath the topsoil around the site.

The story doesn't end with the castle's demise, however. In the early 1900s, a small cottage was built directly on top of the castle ruins, one of several similar houses constructed for First World War veterans returning to the area. This modest dwelling, which still stands today on a low platform formed by the castle's foundations, serves as an unexpected monument to a different chapter of Irish history; one where the stones of medieval power were repurposed to house those who had survived the trenches of Europe. The site thus embodies multiple layers of Irish heritage, from ancient earthworks to medieval strongholds to twentieth-century social housing, all occupying the same patch of Laois countryside.