Countries of the United Kingdom

The countries of the United Kingdom are the non-sovereign countries that make up the UK. They share the same head of state, passport, military and sovereignty under the name of the "United Kingdom of Great Britain and Northern Ireland". 
List
In decreasing order of area they are:

England
Scotland
Wales
Northern Ireland

Terminology
The United Nations and UK government says that the United Kingdom is officially made up of 2 countries (England and Scotland), one principality (Wales) and one province (Northern Ireland).  However, Wales has not formally been a principality since the 16th century with the Laws in Wales Acts. In 2011 the International Organization for Standards updated its standard to define Wales as a country after the Welsh Government asked for the status to be corrected. Northern Ireland has been described variously as a country, province or region.  

References