In Civilization IV, Open Borders is one of the treaties available for negotiation with other civilizations.
Enabled by[]
Researching Writing makes the Open Borders treaty available.
Good and Bad[]
Good[]
- Improves diplomatic relations.
- Allows units to enter the other civilization's territory without declaring war.
- Allows trade with foreign cities accessible to your trade network increasing commerce production.
Bad[]
- Can spark tension with other civilizations.
- Lets other civilizations map out your territory