Bernicia (Brythonic, "Brynaich") was a kingdom of the Angles in northern England during the 6th and 7th centuries AD. It later merged with the kingdom of Deira to form the kingdom of Northumbria.
Its territory is said to have stretched from the Tyne northwards, ultimately reaching the Firth of Forth, while its western frontier was gradually extended westward, encroaching on the Cumbric speaking kingdoms of Rheged, Gododdin and Dunbarton.
The chief royal residence was Bamburgh, and near it was the island of Lindisfarne, which became the see of a bishop.
The first king of whom we have any record is Ida, who is said to have obtained the throne about 547. Aethelfrith, king of Bernicia, united Deira with his own kingdom around the year 604 and ruled the two kingdoms (united as the kingdom of Northumbria) until he was defeated and killed by Raedwald of East Anglia (who had given refuge to Edwin, son of Aella, king of Deira) around the year 616. Edwin then became king.
Following the disastrous Battle of Hatfield Chase on October 12, 633, in which Edwin was defeated and killed by Cadwallon ap Cadfan of Gwynedd and Penda of Mercia, Northumbria again was divided into Bernicia and Deira. Bernicia was then briefly ruled by Eanfrith, son of Aethelfrith, but after about a year he went to Cadwallon to sue for peace and was killed. Eanfrith's brother Oswald then raised an army and finally defeated Cadwallon at the Battle of Heavenfield in 634; after this victory, he reunited Deira with Bernicia. The kings of Bernicia were thereafter supreme in Northumbria, although Deira had its own sub-kings at times during the reigns of Oswiu and his son Ecgfrith.
Bede wrote about Bernicia in his Historia ecclesiastica gentis Anglorum.