In 1921, as the greater part of Ireland seceded as the Irish Free State, Belfast became the capital of the six counties remaining as Northern Ireland in the United Kingdom.

Is postage to Belfast same as UK?

The cost of postage to the UK from the Republic of Ireland depends on whether your item is going to Northern Ireland or the rest of the UK. Postal rates to Northern Ireland are the same as those within the Republic.

Is Northern Ireland considered UK?

Northern Ireland is part of the UK.