The Civil Survey of 1654-6 records that this townland once held a ruined castle, a decaying mill, an orchard and three cabins, all belonging to Theobald Butler. The Down Survey map from the same period shows a castle with an adjacent dwelling in the vicinity of what would later become Millbrook House, suggesting this location has been significant for centuries.

Today, Millbrook House itself lies in ruins, but careful examination reveals its complex architectural heritage. While the main structure dates from the eighteenth or nineteenth century, traces of much earlier stonework from the late sixteenth or seventeenth century can be found in the ruined outbuildings and gate pier. Intriguingly, what appear to be seventeenth-century roof timbers have been repurposed in the roofing of the outhouses, a practical example of how building materials were recycled through the generations. The main house, now rendered and inaccessible inside, guards its secrets well.

Of the original castle mentioned in the historical surveys, no visible remains survive above ground level. The site's transformation from medieval stronghold to later country house reflects the changing fortunes and priorities of rural Ireland over the centuries. Archaeological surveys conducted by Jean Farrelly and Caimin O'Brien have documented these remnants, piecing together a picture of continuous occupation and adaptation at this elevated spot in the Tipperary landscape.