The Belfast Metropolitan Area dominates in population terms, with over a third of the inhabitants of Northern Ireland.

Also unlike the Republic, a large proportion of people in Northern Ireland have a British national identity, although a significant minority identifies as Irish.

Newry Northern Ireland's population density is 133 people per square kilometre – comparable to European countries such as Denmark and the Czech Republic.

Fermanagh and Omagh is the least dense district, with the lowest population (116,812)[18] and greatest land area (2,836 km2).

It includes all of Northern Ireland's least-populous county, Fermanagh (except the townland of Killybane near Fivemiletown), and the largely rural former Omagh district.

Of these 217 wards, 99 are a contiguous area covering most of Belfast, Castlereagh, Lisburn and Newtownabbey.

These wards cover part or all of the 28 largest settlements in Northern Ireland, as well as Warrenpoint, Donaghadee, Ballynahinch, Moira, Maghera and Coalisland.

The vast majority of these wards contain or are near a motorway, dual carriageway or train station.

Furthermore, 50.02% of Northern Ireland's population lived in the most population-dense contiguous area of 216 electoral wards.

These wards cover part or all of the 10 largest settlements, and almost entirely track Northern Ireland's rail lines, motorways and dual carriageways.

The exceptions are a spur towards Armagh city; and a string of villages between Ballymena and Limavady.

The town of Dungannon in Mid Ulster District Council has a bigger share of immigrants than any town in Northern Ireland, while Derry City and Strabane has the smallest share of immigrants.

This is an estimate of the minimum amount of emigration, since deaths are not broken down by country of birth, so some of those will not have been born in Northern Ireland.

Doing the same analysis by age shows that this is consistent with the actual number of those born in Northern Ireland from the 2021 England/Wales census,[32] where about 40% of emigrants have settled in England or Wales.

[40][41] The following table shows the ethnic group of respondents for the following censuses 98.28% 0.13% English is by far the most commonly spoken language in Northern Ireland.

In 2011, the census question was modified to ask about Ulster Scots alongside Irish.

[49] Main language of all usual residents aged 3 and over Ability in Irish of all usual residents aged 3 and over in the Census[52][53] Ability in Ulster Scots of all usual residents aged 3 and over in the Census[56] Northern Ireland has a highly educated and literate population, particularly among the younger generations.

The following shows the educational attainment, shown by highest qualification received, at different ages for adults, in the 2021 census[58] The census defines the levels as follows: Younger adults, aged 18–30, are the highest ever qualified group.

There is a large gender gap with 10% more females than males receiving Level 4 or above qualification.

Even among the younger, more qualified, NI residents, Northern Ireland has the highest proportion of people with no qualifications.

Geographically, using Religion instead of Religious Background does not change the areas where Catholic outnumber Protestants, or vice versa, but results in some regions where a majority turns into a plurality.

Many in Northern Ireland have a British national identity and view the English, Scots and Welsh as fellow members of their common nation while regarding people from the Republic of Ireland as foreigners.

Although there is a strong correlation between religion and national identity, Catholics tending to identify as Irish and Protestants tending to identify as British, this is not an absolute relationship, and the correlation is weaker amongst Catholics than it is amongst Protestants.

Northern Irish identity was slightly more likely amongst Catholics than amongst Protestants, and it varied little according to geography.

Through an agreement between the Irish Government and Post Office Ltd, post offices in Northern Ireland provide a service where customers can apply for an Irish passport, alongside their service where customers can apply for a British passport.

[87][88] The following table shows the number of passport applications from within Northern Ireland since the 2021 census.