Felin Mydroilyn

Felin Mydroilyn is a building constructed from rubble stone with a slate roof, featuring one storey and a loft. The north gable end has a broad, cambered-arched cart entry at ground level, which is framed by stone voussoirs and has double plank doors. To the right, there is a lean-to addition that includes a ground floor door with stone voussoirs and a damaged opening above it. The east side provides access to the upper floor from a raised bank, featuring a door and a window.

At the south end, there is a large iron mill-wheel with timber spokes and buckets, which has been enclosed in a stone building that matches the roof height of the original structure. This enclosure has a tall arched opening on the west side, also framed by stone voussoirs. The building has not been inspected recently but is said to contain remaining mill machinery and a single loft floor.