Britannia Superior was a province of Roman Britain created after the civil war between Septimius Severus and Clodius Albinus. Although Herodian credits Severus with dividing Roman Britain into the Northern territory of Britannia Inferior and the Southern territory of Britannia Superior, modern scholarship argues that it is more likely that Caracella was the person who made the split sometime in the early 3rd century CE. The previous British capital Londinium remained the centre of Britannia Superior while Eboracum, or modern York was the capital of Britannia Inferior. Epigraphical evidence shows that Upper Britain encompassed approximately what is now Wales, southern England and East Anglia. However, the official boundary between Britannia Superior and Inferior is still unclear.

Roman Britain was the territory that became the Roman province of Britannia after the Roman conquest of Britain, consisting of a large part of the island of Great Britain. The occupation lasted from AD 43 to AD 410.