The Kingdom of Powys was a Welsh successor state, petty kingdom and principality that emerged during the Middle Ages following the end of Roman rule in Britain. It very roughly covered the northern two-thirds of the modern county of Powys and part of today's English West Midlands. More precisely, and based on the Romano-British tribal lands of the Ordovices in the west and the Cornovii in the east, its boundaries originally extended from the Cambrian Mountains in the west to include the modern West Midlands region of England in the east. The fertile river valleys of the Severn and Tern are found here, and this region is referred to in later Welsh literature as "the Paradise of Powys".

The Cornovīī were a Celtic people of the Iron Age and Roman Britain, who lived principally in the modern English counties of Cheshire, Shropshire, north Staffordshire, north Herefordshire and eastern parts of the Welsh counties of Flintshire, Powys and Wrexham. Their capital in pre-Roman times was probably a hillfort on the Wrekin. Ptolemy's 2nd-century Geography names two of their towns: Deva Victrix (Chester) and Viroconium Cornoviorum (Wroxeter), which became their capital under Roman rule.