Domnonée (Breton: Domnonea) is the modern French version of the Latin name Dumnonia (or Domnonia), which denotes a kingdom in northern Brittany founded by migrants from Dumnonia (Devon) in Great Britain.

The Latin form Domnonia can refer to either the British or the Breton kingdom.In the Armorican peninsula (Brittany), the kingdom is said to have been founded in the declining phase of the Roman empire.

It includes Trégor, Dol-de-Bretagne through to Goélo and Penthièvre.

Its leaders are referred to as Princes, but later obtain the title King of the Bretons.

Domnonée retains close political links between the Brythonic (Celtic) territories in Britain (Wales, Cornwall, Devon), and the newly created Armorican Britain (Brittany), and it hosts many kings, princes, clerics and other leaders who come over from Celtic Britain.

The sea is a unifying rather than divisive factor.

In the traditions relating to the settlement of Brittany by the Bretons, there are several kingdoms of this kind.

Reliable information about the history of Domnonée is limited.

A list of Princes includes Riothamus, who led a British force against the king of the Goths.

In 53, the principality becoms the cener of the Breton kingdom.