Settlement can be founded 5 tiles from each other.
Independents will 6 tiles from Major Civilizations.
Here is the 4 tiles version: https://forums.civfanatics.com/resources/4-tiles-min-city-range.32286/
Independents will 6 tiles from Major Civilizations.
Here is the 4 tiles version: https://forums.civfanatics.com/resources/4-tiles-min-city-range.32286/