Northern Ireland is the smallest of the four countries of the United Kingdom in terms of both area and population, containing 2.9% of the total population and 5.7% of the total area of the United Kingdom. It is the smaller of the two political entities on the island of Ireland by area and population, the other being the Republic of Ireland, a sovereign state independent of the United Kingdom since 1922. Northern Ireland contains 28.3% of the total population and 16.5% of the total area of the island of Ireland.
Northern Ireland, as recorded by the UK Census 2011, has a population of 1,810,863, an increase of 125,800 (7.5%) over the ten-year period since the last census. The population density is 133 people per km2, about half that of the United Kingdom as a whole but about twice that of the Republic. The Belfast Metropolitan Area dominates in population terms, with over a third of the inhabitants of Northern Ireland.
Like Britain (but unlike the Republic of Ireland), Northern Ireland has a large proportion of Protestants and its people speak dialects of English heavily influenced by the Scots language, largely because of settlements of Protestants in Ulster in the 17th century, such as the Plantation of Ulster. Also unlike the Republic, a large proportion of people in Northern Ireland have a British national identity. Many people in Northern Ireland have a Northern Irish identity, whether in addition to a British or Irish identity or by itself.
In 2001, 91.0% of the population were born in Northern Ireland, 7.2% were born in other parts of the UK and Ireland, and 1.8% were born elsewhere. By 2011, the number of immigrants from outside the UK and Ireland had risen to 4.3%, while the number born within them fell to 6.7%. The highest number of non-British/non-Irish immigrants are in Belfast, followed by Craigavon Urban Area and Dungannon. Dungannon has a bigger share of immigrants than any town in Northern Ireland, while Strabane has the smallest share of these immigrants.