So once it's removed it never can come back even if your lands fall into decades long civil war, the bordering provinces pillaged and devoid of civilisation, the wastelands will keep being civilised enough to not spawn barbarians?Since Barbarian strongholds are in impassable locations they cannot be directly interacted with, however the governor policy for Civilization Effort in an adjacent province can increase the civilization level in the stronghold's location, and eventually downgrade, and then remove the stronghold.