Powis Castle sits on a hillside just to the south-west of Welshpool. The castle's last private owner was the 4th Earl. His son, Mervyn, Lord Clive, served in the RAF and was shot down and killed over the Bay of Biscay in 1942. With no direct heir, the Earl chose to give the castle to the National Trust in 1952.

Between 1939 and 1946 the Welsh Girls School, Middlesex, was based in the castle.