Celtic Sea

The Celtic Sea is an arm of the North Atlantic Ocean lying south of Ireland and west of the south-western peninsula of England. Its western boundaries are undefined, but to the east it divides into two arms: St George's Channel, which divides Ireland and Wales, and leads into the Irish Sea; and the Bristol Channel, which divides south Wales from south-west England. The Celtic Sea contains oil and natural gas reserves; those which lie beneath the Irish continental shelf are commercially developed.