Castlereagh Postcodes County

Castlereagh is a suburban county area in Northern Ireland, located to the south and east of Belfast. It developed largely as a residential district, shaped by its proximity to the city while retaining a quieter, more settled character. The landscape includes gentle hills, established neighbourhoods and pockets of open land, giving the area a balance between urban convenience and a less crowded pace of life.

The area grew significantly during the twentieth century as Belfast expanded, with Castlereagh becoming home to many people working in the city but seeking a more suburban setting. Local centres developed to support everyday needs, including schools, shops and community facilities. While closely linked to Belfast, Castlereagh maintains its own identity, shaped by long standing communities and familiar local surroundings. Strong residential roots remain a defining feature of the area.

Castlereagh also benefits from access to green space, including parks, river corridors and nearby countryside that support walking and outdoor activity. These natural elements soften the built environment and contribute to a sense of wellbeing for residents. Taken together, Castlereagh offers a steady blend of suburban living, local community and accessible green space, giving it a calm and dependable character within the wider Belfast area.

3,943
Postcodes
5
Districts
166,192
Population
Northern Ireland
Country

Postcode districts in Castlereagh

DistrictPost townPostcodesPopulation
BT23 Newtownards 1,462 53,059
BT5 Belfast 881 38,809
BT8 Belfast 635 28,807
BT6 Belfast 562 30,004
BT16 Belfast 403 15,513

Frequently asked questions

How many postcodes are in Castlereagh?

There are approximately 3,943 postcodes in Castlereagh.

How many postcode districts are in Castlereagh?

Castlereagh contains 5 postcode districts.

What is the population of Castlereagh?

The postcode districts in Castlereagh have a combined population of about 166,192.