Caus Castle is a ruin of a hill fort and medieval castle in the civil parish of Westbury in the English county of Shropshire. It is situated up on the eastern foothills of the Long Mountain guarding the route from Shrewsbury, Shropshire to Montgomery, Powys, on the border between England and Wales. It was destroyed during the English Civil War and has been in ruins since.

The Welsh Marches is an imprecisely defined area along the border between England and Wales in the United Kingdom. The precise meaning of the term has varied at different periods.