5 tiles apart?

[Zaimejs]

Beat me to it. How do I change the spacing?

 

[Glassmage]

C:\Program Files\Steam\steamapps\common\sid meier's civilization v\assets\Gameplay\XML\GlobalDefines.xml

find the line with MIN_CITY_RANGE, it should have the value "3" which means minimum 3 tiles between 2 adjacent cities. Change the numbers to whatever you want.