Wales is a small principality within the United Kingdom. Daniel Jackson once mentioned that he went there to learn the ancient Celtic Language. Later Jackson used an old Arthuran legend of "Gwlad Gan Brenhinol Gwir", Welsh for "Land of Royal Truth" to find the location of the Sangraal. Earth
On the stairs to the briefing room in Stargate Command, among the few screens is what appears to be a weather monitor with Wales and the Irish Sea on it.
- Wales on Wikipedia