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.

Westbury is a village and parish in Shropshire, England. It includes the settlements of Caus Forest, Lake, Marche, Newtown, Stoney Stretton, Vennington, Wallop, Westbury, Whitton, Winsley and Yockleton. It lies 8 miles (13 km) west of Shrewsbury, close to the Wales-England border. It is located at 135 m altitude. It had a population of 1,352 according to the 2011 census. In 2005, Westbury parish expanded with the annexation of half of the former Wollaston parish.