Every province has a civilization level.
Any fractional remainder is dropped after the contributions are summed.
A safe haven city, and inn, and a mine would yield a level of civ-3. A province with a safe haven city surrounded by provinces with no cities or buildings would have a level of civ-2. The surrounding provinces would then rise to civ-1. A province containing a castle would have a level of civ-1. The maximum civilization level a province may have is civ-6.