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. | 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. |