All parts of a country are rarely equally affected by political violence. Yet statistical studies largely fail to address sub-national conflict dynamics. We address this gap studying variations in 'routine' and 'episodic' violence between Indonesian provinces from 1990 to 2003. Within a grievance framework, the article focuses on the violence potential of resource scarcity and population pressure, as well as inter-group dynamics related to polarisation and horizontal inequality. Demographic pressure and inequality seem to have little effect in isolation. However, in provinces where population growth is high, greater levels of inequality between religious groups appear to increase the violence risk.