Modern Celtic Nations
The Celtic nations are territories in western Europe where Celtic languages or cultural traits have survived. The term "nation" is used in its original sense to mean a people who share a common identity and culture and are identified with a traditional territory.
The six territories widely considered Celtic are Brittany, Cornwall, Wales, Scotland, Ireland, and the Isle of Man, commonly referred to as the "Celtic fringe". In each of these six nations a Celtic language is still spoken to at least some degree today. No Celtic language has been spoken in northwestern Iberia in the recent past, but Galicia is also considered Celtic by some.
Of the six languages spoken, three belong to the Goidelic or Gaelic branch (Irish, Scottish Gaelic, and Manx) and three to the Brythonic or Brittonic branch (Welsh, Cornish, and Breton).
Portions paraphrased from the "Celtic nations" Wikipedia entry