Tan-yr-Ogof Farmhouse including adjoining arch and walls to E

This is a C-shaped farmhouse constructed from local limestone rubble, with slate roofs. The main block is two storeys high and rectangular, featuring a castellated appearance along the road-facing side and a mono-pitched roof to the rear. Lower, gabled wings adjoin to the north, creating a small garden area, with the farmyard located to the east.

The main section has crenellations along its length, and corbelling on the shorter east side. Centrally, a parapetted, projecting porch has a blocked Tudor-arched entrance on the front face and a pointed arched window on the right return, with cusped head and small-pane glazing. A flat roofed opening gives access onto the porch. A projecting chimney, in the form of a turret, rises from the corner between the porch and the main block; the upper section is sham-machicolated with louvre holes. A pointed-arched first-floor window is located on the east return of the main block, with a flat-arched window below ground level. The current farmhouse entrance is at the rear, accessed through a single-storey, hipped-roofed stone porch situated between the main block and the wing to the left. The porch has a segmental entrance and a modern boarded inner door. Three four-pane late Victorian sash windows are set under the eaves on the first floor. A cambered-headed, modern glazed door is located to the right of the porch, with Tudor-arched brick openings nearby, the first containing a modern window, and the second blocked. Further entrances are found in the lower, storeyed wing to the right. The wing to the left is single-storeyed and features a corbelled-out upper gable with modern bargeboards and a modern window below, alongside arched windows which were formerly entrances.

Adjoining the main block to the east, a stepped-down wall, incorporating sham-machicolations and crenellations, extends slightly back from the road. A large Tudor-arched entrance provides access to the farmyard, with modern boarded half-gates. The wall then steps down again and advances for approximately 6 metres southwards towards the road as a plain rubble wall. This terminates in a cylindrical turret with a corbelled-out, but un-crenellated, upper section. A further section of the wall runs eastwards for approximately 25 metres before returning northwards to enclose the farmyard on the east side, and it is crenellated with large, forward projecting, corbelled out merlons.

The interior of the farmhouse has been modernised.