In HWW, the provinces of a country should follow the borders of real-live subdivisions of the country. You can roughly see this with Canada in HWW. For example, I can conquer X amount of Provinces from the USA to "form" the state of Texas.
Example of where this could be applicable are the states in the USA, the provinces in Canada, the oblasts in the Soviet Union, the administrative divisions of Germany, and the socialist republics of Yugoslavia.
Example of where this could be applicable are the states in the USA, the provinces in Canada, the oblasts in the Soviet Union, the administrative divisions of Germany, and the socialist republics of Yugoslavia.