From Cambridge dictionary:
He was born in the small town of Castleford, in Yorkshire.
I'm not sure whether I understand this correctly. Is it a town called "Castleford"? Or there is a bigger place like a county or state contains a town called Castleford, hence we say "the town of it" as it is the capital of the state.
Why we don't just say "in a small town called Castleford"?
I've never heard "the nation of England" before. But I wonder whether this is a correct way to say "England".