Llwyn-y-Celyn farmhouse was built in 1705 (dated), with two wings which were probably added in the early C19. At this date the rear wing was converted to a separate dwelling. Since this date, the house has apparently had little alteration apart from re-windowing on the main elevation in the late C20 after the farm was sold from the Itton estate.
The house is rendered and painted throughout, presumably over rubble stone, and has Welsh slate roofs. It is a T-shaped block with the foot of the T stretching back behind the rectangular main range. There is an in-line wing added to the left of the main front and the rear wing has a later wing added at right angles. The main entrance elevation has a three bay front with a central entrance. This is in a gabled porch with a square headed opening, and it has a C19 door within. There are two storeys and attic although the kitchen wing to the left, has one storey and attic. All the windows to the front are modern steel casements. There is a steeply pitched roof with two gabled Victorian dormers and large gable stacks at either end which are external to the building. There is also a red sandstone plaque on the gable with the date in relief 1705.
The interior is said to have chamfered ceiling beams, a dog-leg stair with oak treads and a principal rafter roof, all as might be expected in this type of house. This agrees with Fox and Raglan who also recorded a two room plan with parlour to the left and hall to the right, and a vaulted cellar under the rear wing. They say that the framed staircase is top-lit and has acorn newels.
It is listed as a regional farmhouse which is dated 1705 and which despite some superficial changes still retains its character.
