National infrastructures form critical components of present day societies because they provide services leading to economic prosperity and social well being. Disruptions due to extreme hazard events have shown the growing vulnerability and frequent breakdowns of national infrastructures. Due focus on critical infrastructure vulnerability and risk analysis is important in planning for risk reduction. This research focuses on the risk of failures of national infrastructure networks due to extreme spatial hazard events that have the potential of causing widespread infrastructure disruptions. Our aim here is to develop a spatial risk assessment framework that calculates infrastructure risk from multiple infrastructure network failure configurations resulting from exposure of extreme hazard loading. We have formulated and implemented a methodology for estimating reliability, disruption and overall risk for spatial infrastructures. The implementation of the methodology is discussed here through an example case study analysis on national scale extreme hazards and infrastructure networks.