Ty-Mawr, Castell Caereinion, is a significant survival of a medieval hall house of high gentry status which, following restoration in 1997-8, once again serves as a dwelling. Evidence from dendrochronolgy demonstrates that the hall was constructed around 1460. Subsequent later additions include the insertion of a smoke hood above the fire in 1630 - 31 which accompanied the creation of an upper floor in what was originally the hall. The house stands on level ground created by cutting into the hillside to the northeast with the spoil used to create a platform to the southwest. The structure itself is of mixed aisled and base-cruck form and includes a central hall with a cross-passage between two entrances to the south-east and north-west. The roof is hipped and probably originally included vents at either end to remove smoke.