William Herbert, 1st Baron Powis KB was a Welsh politician who sat in the House of Commons at various times between 1597 and 1629.

Powis Castle is a medieval castle, fortress and grand country house near Welshpool, in Powys, Wales. The seat of the Herbert family, earls of Powis, the castle is known for its formal gardens and for its interiors, the former having been described as "the most important", and the latter "the most magnificent", in the country. The castle and gardens are under the care of the National Trust. Powis Castle is a Grade I listed building, while its gardens have their own Grade I listing on the Cadw/ICOMOS Register of Parks and Gardens of Special Historic Interest in Wales.