A comprehensive surge system consists of well-balanced capacity and capability in personnel (staff), supplies and equipment (stuff), and physical structure and management infrastructure (structure). This chapter describes this 3S Surge System. The complexities surrounding surge capacity start with the myriad of definitions related to medical surge. The Metropolitan Medical Response System (MMRS) is a locally managed emergency preparedness and response system that is integrated into state and federal programs. Hospitals and other healthcare facilities must have plans to expand their capacity to manage a surge in the number of patients needing care during a disaster. An important source of surge response within the US is provided by formal State to State requests and offers of support. Evidence-based data on efficacy of interventions and best outcomes in surge capacity are limited. Further studies on the efficacy of interventions and their impact on individual-based versus population-based outcomes are needed.