Crai is a village in the Brecon Beacons National Park in the county of Powys, Wales. It gives its name to the community of Cray, within which are the hamlet of Felin-Crai and a large number of dispersed farms around the valley of the Afon Crai. The river is dammed 2 km / 1.5 mi southwest of the village to form Cray Reservoir. The name may derive from Welsh 'crai' meaning rough and referring originally to the nature of the river.