Grand Duchy of Eraystor

The Grand Duchy of Eraystor was located in the southern portion of Emerald Island, along the north coast of Eraystor Bay.

The capital city of the grand duchy was Eraystor, which was also the capital of the entire Princedom. 

Given its inclusion of the capital, it was likely attached to the Crown, in a manner akin to the monarch of Chisholm also holding the Duchy of Cherayth.