4 Tros yr Afon

4 Tros yr Afon is a late-Georgian style, two-storey house featuring whitened roughcast walls and a slate roof, part of a row with Nos 1-3 Tros yr Afon, and roughcast stacks. The entrance front has two bays, with a doorway on the left that includes a fielded-panel door with inserted glazed panels and a four-pane overlight above. The windows are 12-pane hornless sashes, with the upper storey windows being shorter.

To the left, there is a higher projecting gabled two-bay wing adorned with arcaded barge boards and a finial, along with projecting eaves. This wing has large 12-pane hornless sash windows beneath hood moulds on the lower storey and a central canted oriel window in the upper storey featuring a mid-20th century steel-framed casement. An external stack is located on the left-hand wall of this wing. Further left, there is a 12-pane sash window on the lower storey, along with replacement windows on the upper storey and a half-dormer.

There is a single-bay extension aligned with the main range, built over the vehicular passage, which has a four-pane sash window. Inside the passage, there is an eight-pane hornless sash window and a replacement half-glazed door. The rear elevation of the extension features two two-pane sash windows. Additionally, there is a short two-and-a-half-storey, two-window gabled rear wing with a higher eaves line, which has a replacement half-glazed door on the left, a two-light window on the lower storey, 12-pane horned sash windows on the middle storey, and a replacement attic window. The right side wall facing the vehicular passage includes an inserted three-light window on the lower storey and a four-pane horned sash window on the upper storey. The property has not been inspected.