The State of Oregon has unique seismic risks associated with its location adjacent to the Cascadia Subduction Zone. The nature and probability of this risk are examined. Because this risk was only recently identified, most of the state's bridges are designed for little or no seismic loads, and thus require a comprehensive program of seismic retrofit. Divided into Phase 1 (superstructure) and Phase 2 (substructure), the retrofit needs have been identified with respect to structure vulnerability and criticality, and work has been proposed and prioritized to account for cost-effectiveness and lifeline classification.