Why is North song called the old north state?

The North Carolina state anthem, "The Old North State", is not called North Song. It was written in 1835 and is titled "Carolina". The song's lyrics pay homage to the state's natural beauty, its history, and its people. The verse below is the part that makes the reference to the old North state.

Here we hail to the Old North State

And proudly tell her fame.

Her sons are brave, her daughters fair,

Her climate is the same

As Eden's lovely vale, my boys,

As Eden's lovely vale.