Effective response to large incidents requires real-time collaboration among multiple agencies and jurisdictions. Emergency Operation Centers (EOCs), activated during an incident, use many different systems to support operations and situational awareness. Most EOCs are neither interoperable nor interconnected, which makes it very difficult to coordinate resources and inform the decision makers. The EOC-interconnectivity (EOC-I) project defined a set of data exchanges for requesting and responding to incident and resource information enacted and acquired during the incident. The NIEM-conformant exchange and prototype system is based on emerging Internet technologies and designed to improve information sharing, situational awareness, and collaboration by regional EOCs during multijurisdictional emergencies to maximize the situational awareness for first responders. The EOC-I project was developed through interactions with state, regional, local, and tribal first responders in the Seattle and Cincinnati regions as well as in coordination with FEMA National Incident Management System (NIMS) multiple working groups.