Original constructed in the late nineteenth century (c.1870?80) as a fishing lodge, Gelligemlyn Hall was greatly extended in 1903 for W. H. Lee with an additional addition to the north-east in 1912. The structure was later subdivided into multiple properties. The main block of the building is of two-stories and five bays, oriented west-east with a hipped-roofed conservatory to the east and an extensive further block behind. It is approached by a path through an ornamental front garden. It is constructed of rough-faced stone with imitation timbering to the second storeys of the first, second, forth and fifth bays. The third and fifth bays are gabled and there are prominent, tall stone chimneys throughout.

(Sources: Richard Haslam, Julian Orbach and Adam Voelcher, The Buildings of Wales: Gwynedd (New Haven: Yale University Press, 2009), p. 603; Digitised Postcard Images of Gellgenlyn Hall, Produced by Parks and Gardens Data Services, Peter Davis Digitised Postcards Collection, NMRW)
A.N. Coward, RCAHMW, 25.02.2019