Northern Ireland is variously described as a country, province, or region, which is part of the United Kingdom. Located in the northeast of the island of Ireland, Northern Ireland shares a border to the south and west with the Republic of Ireland. In 2011, its population was 1,810,863, constituting about 30% of the island's total population and about 3% of the UK's population.

Wales is a country that is part of the United Kingdom. It is bordered by England to the east, the Irish Sea to the north and west, and the Bristol Channel to the south. It had a population in 2011 of 3 million and has a total area of 20,779 km2 (8,023 sq mi). Wales is often used as a unit for measuring area.