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

C-shaped farmhouse of local limestone rubble with slate roofs. The house consists of a main 2-storeyed, rectangular castellated block, with mono-pitched roof to rear behind a battlemented, road-facing front. Lower gabled wings adjoin to the N enclosing a small garden area with the farmyard to the E. The main section has crenellations to the long road side and both crenellations and corbelling to the shorter E side. In the centre of the main face is a parapetted, open porch projection with blocked Tudor-arched entrance to the front and pointed-arched window to the R return; cusped head and small-pane glazing. The porch projection has a flat roof with pointed-arched opening giving onto it. At the R corner, extruded in the angle between porch and main block, is a projecting chimney in the form of a turret; sham-machicolated upper section with louvre holes. Further pointed-arched first-floor window to E return of main block, with flat-arched window below. The farmhouse entrance is presently to the rear, via a single-storey, hipped-roofed stone porch, extruded between the main block and the lower wing at L; segmental entrance and modern boarded inner door. Three 4-pane late Victorian sashes to the first floor, under the eaves. Cambered-headed modern glazed door (small pane) to R of porch with Tudor-arched brick openings beyond, the first with modern window, that beyond blocked. Further entrances to lower storeyed wing to R. The wing to the L is single storey and has a corbelled-out upper gable with modern bargeboards; modern window below. Arched windows to sides, contained within former entrances.

Adjoining the main block to the E and set back slightly from the roadside, a stepped-down section of sham-machicolated and crenellated wall. This has a large Tudor-arched entrance below, the main access to the farmyard; modern boarded half-gates. Beyond this the wall steps-down again and advances for some 6m southwards towards the road as a plain rubble wall; this terminates in a cylindrical turret with corbelled-out, though un-crenellated upper section. From the gateway the wall also continues eastwards for some 25m before returning northwards to enclose the farmyard on the E side. This section is crenellated, this has large crenellations, the merlons of which project forwards and are corbelled out.

Plain, modernised interiors.