Its undulating roof, verandahs trimmed with rustic oak posts, lattice glazing, and pointed upper windows give it the appearance of an elaborate Alpine fantasy, which is precisely the point. This is the Swiss Cottage, a cottage orné, a fashionable early nineteenth-century building type designed to look artfully rural while providing comfortable, even refined, accommodation for aristocratic occupants who wanted a retreat from the formality of their main house. The metal fencing surrounding the lawns was crafted to resemble natural tree trunks and branches, continuing the conceit right to the boundary of the grounds.

The building was constructed between 1810 and 1814 for Richard Butler, the 10th Baron Caher, who would later become the first Earl of Glengall. The design is attributed, at least in popular tradition, to John Nash, the architect better known for his work on Regent Street and the Royal Pavilion at Brighton. Inside, the illusion of rusticity gives way to considerable sophistication. The ground floor opens into a round hallway with a cobweb parquet floor and a timber spiral staircase. Two rooms lead off from it: the Dufour Room to the west and the Music Room to the east. The Dufour Room takes its name from the wallpaper still visible on its walls, a panoramic design by the Parisian manufacturer Joseph Dufour, depicting scenes of Constantinople. The Music Room contains a fireplace with rustic timber-effect metal detailing and a mirror above it bearing a portrait of Lady Glengall. A door on the north side of the hallway opens onto limestone steps descending to an underground kitchen and cellar, connected also to the exterior by a vaulted, whitewashed tunnel, ensuring that the business of domestic life remained well out of sight.

The cottage sits at the southern end of the parkland behind Cahir House, the Butler family's principal residence, and commands a clear view over the Suir. The T-plan layout, with its bowed two-storey timberwork bay and verandahs on almost every elevation, is best appreciated by walking the full perimeter before going inside, where the sloping ceilings, angled window openings, and period furnishings give each room a slightly theatrical, carefully composed quality.