The United Kingdom includes countries.
Cardiff ( Caerdydd } } [ kairˈdiːð , kaˑɨrˈdɨːð ] ) is the capital and largest city in Wales and the eleventh-largest city in the United Kingdom . Northern Ireland ( Tuaisceart Éireann [ ˈt̪ˠuəʃcəɾˠt̪ˠ ˈeːɾʲən̪ˠ ] ; Ulster-Scots : Norlin Airlann ) is a country of the United Kingdom located in the north-east of the island of Ireland . The United Kingdom of Great Britain and Northern Ireland , commonly known as the United Kingdom ( UK ) or Britain , is a sovereign country in western Europe . The United Kingdom consists of four countries -- England , Scotland , Wales and Northern Ireland .