Llandyfan House is part of Llandyfan Farmstead (NPRN 407331). It is sited immediately south of St Dyfan's Church (NPRN 302028) and was reportedly an inn in the eighteenth century, said to have been used particularly by pilgrims visiting St Dyfan's well (NPRN 418246). The house is a Grade II listed building, considered a good example of an eighteenth century farmhouse, and to have group value together with its outbuildings (NPRN 31618 and St Dyfan's Church. In 1841 the house was recorded as being in the ownership of Lord Dynevor, and as being occupied by Jane Morgan.

The house is thought to have originated in the seventeenth or early eighteenth century, but was altered around the late eighteenth or ealy nineteenth century. It is constructed of rubble stone with a stone-tile roof and a stone end-wall and ridge stacks. The building consists of two storeys and attic, front lean-to, rear lean-to and porch. The windows in its three-window range have unusual horned sashes, with five over five panes. The porch is constructed of squared red sandstone, similar to the church, with a pointed arch and bargeboards. The south end wall has a massive projecting stone stack with a square shaft and offsets both sides. Internally, the house has stone-flagged floors and original fireplaces with new oak bressumers. There are chamfered ceiling beams throughout the house and chamfered wooden door lintels. The oak plank doors are original, and the staircase is reclaimed oak. There is one dairy slab in situ in the rear lean-to.

Sources include:
Cadw, Listed Buildings Database

N Vousden, RCAHMW, 21 January 2012