BT postcode area

The BT postcode area (also called the Belfast postcode area) is how each area in Northern Ireland has postcodes. Northern Ireland was the last part of the United Kingdom to get post codes. The BT postcode area was made between 1970 and 1974. 
Belfast.
The Belfast post town districts are BT1 to BT17, BT58 and part of BT29. "BT" is short way of saying "Belfast". The postcode for Belfast city centre starts "BT1". The Royal Mail office in Belfast has a postcode of BT1 1AA. 
Rest of Northern Ireland.
The rest of Northern Ireland has 43 other post towns. The post town districts for the 43 post towns are BT18 to BT57, BT60 to BT82, BT92 to BT94 and part of BT29.