Provinces
From Conflict of Nations Wiki
Provinces are the life of your strategic conquest, and will prove to be useful as outposts, airbases, navy bases and more. They have properties attached such as Population, Morale, Production, Terrain type. Healing/Defensive values and Victory points.
Cities
You can also see the text 'Homeland City', 'Occupied city' or 'Annexed city' written in the province bar which is there to let you know of the different states a city can be in. Cities have the largest strategic value, allowing you to use them for many reasons and purposes.
Homeland City
The name being self explanatory, Homeland cities is a city which you own at the start of your game. These cities will have the best starting stats, with high morale and population, so be sure to take care of them!
Occupied City
In you conquest for global domination, the populus do not appreciate your enforcement into their homeland. Morale is capped and stats are generally low, you will not be able to mobilise units but you are able to construct in the city and use it as a strategic base.
Annexed City
Annexed cities remove the Morale cap of an Occupied City and allow you to start mobilising units. As a result of this increase in Morale, also earns you a higher population rate and better resource gathering. To Annex a city, select it in your construction list.