Allt Lwyd is a top of Waun Rydd in the Brecon Beacons National Park, in southern Powys, Wales.

The summit is heathery and marked by a small pile of stones.

It is found at the end of Waun Rydd's south-east ridge.

It overlooks Talybont Reservoir, and has the Talybont Forest on its steep flanks.

This Powys location article is a stub.