Architect Hillair was designed by the New York architectural firm Snelling & Potter, an office active in the late nineteenth and early twentieth centuries and known for substantial residences for wealthy clients. Their work at Hillair demonstrates a confident command of Georgian Revival principles combined with a pragmatic willingness to adapt historical forms to modern country-house requirements. In this commission, the architects accommodated the owner’s insistence on features—most notably a full surrounding veranda and a prominent porte-cochère—that departed from strict Georgian precedent while preserving the overall classical discipline of the design. Hillair was among the firm’s most ambitious residential projects and was widely published soon after its completion.

Architectural Description Completed in 1904, Hillair was a large Georgian Revival mansion set on elevated ground in White Plains, commanding long views over the surrounding countryside and, on clear days, toward Long Island Sound. The plan was rigorously symmetrical, a defining requirement of the Georgian mode, with the principal façade oriented to the south. The entrance was placed on the north side, where a semi-hexagonal porte-cochère projected from the elevation. Although eclectic in character, this feature was judged by contemporary critics to be both practical and visually successful.

The house was constructed of gray Indiana limestone laid in coursed ashlar. Early designs had specified brick with limestone trim, but the decision to execute the entire exterior in stone was widely regarded as enhancing the dignity and coherence of the composition. Classical Ionic columns and a continuous entablature articulated all sides of the building, reinforcing its formal unity. A veranda encircled the house, an element insisted upon by the owner and integrated into the overall design with considerable skill. The massing was substantial, with three principal stories and a low-pitched roof, producing a commanding but restrained silhouette appropriate to its hilltop site.

Interior Description The interiors of Hillair were conceived on a scale commensurate with the exterior, reportedly comprising thirty rooms or more. Public spaces were arranged along formal axes, with generous halls and reception rooms designed for entertaining. Period photographs show large, well-proportioned rooms furnished in a restrained classical manner, with fireplaces serving as focal points in principal rooms.

The entrance hall featured a sweeping staircase with a curved ascent, elaborate iron or carved balustrades, and classical detailing consistent with the Georgian Revival exterior. Drawing rooms and living rooms were arranged en suite, allowing for circulation during large gatherings, while the dining room was treated as a ceremonial space with rich finishes and carefully composed proportions. Ceilings varied between plaster with classical ornament and more subdued treatments in secondary rooms. Throughout the interior, the emphasis was on symmetry, axial planning, and a sense of ordered grandeur rather than exuberant ornament.

History Hillair was built as the country residence of Paul Gibert Thebaud, a prominent commission merchant associated with the firm of Bouchard, Thebaud & Co. Thebaud belonged to a wealthy New York family and maintained a townhouse on Madison Avenue, using Hillair as a suburban retreat during the height of White Plains’ development as an elite residential enclave in the early twentieth century. His wife, Mathilde Reynal, linked the estate to the broader Reynal family landholdings and social network in the area.

At the time of its completion, Hillair was regarded as a showplace and was prominently featured in The Architectural Record in July 1904, with exterior photographs, interior views, and a site plan. Contemporary commentary emphasized the house’s visibility across the landscape and noted that, although the building itself was complete, the surrounding grounds would require years to mature fully.

By the 1920s, pressures of suburban expansion led to the subdivision and repurposing of much of the surrounding land. Associated structures, including stables, were adapted for new uses such as riding facilities. The house itself did not survive intact into the later twentieth century and was eventually demolished or lost through redevelopment. Today, its memory is preserved primarily through period publications, photographs, and local toponyms such as Hillair Circle, which recall the presence of one of White Plains’ most imposing Gilded Age estates.