OBJECTIVE: Identify lessons about the public health emergency preparedness system from after action report/improvement plans (AAR/IPs) authored by state and local health departments following the 2009 H1N1 influenza pandemic. DESIGN: Potentially generalizable findings were collected during a workshop attended by representatives from the Centers for Disease Control and Prevention (CDC), state and local public health departments, and other organizations that prepared 2009 H1N1AAR/IPs. PARTICIPANTS: Workshop participants included state and local health department personnel who had submitted AAR/IPs to the CDC for review. MEASURES: Workshop participants were asked to consider the question: What did you hear from other jurisdictions that resonated with your own experience and could be a generalized finding? RESULTS: Workshop discussions revealed potential lessons concerning: (1) situational awareness during the initial response; (2) resource mobilization and legal authority; (3) the complexity of vaccine distribution and administration; (4) balancing emergency response and routine operations; (5) communication and coordination among the many independent actors in the public health system; and (6) incident management in a long-duration incident. CONCLUSIONS: The response to the 2009 H1N1 influenza pandemic provides an opportunity to learn about the public health system's emergency response capabilities and to identify ways to improve preparedness for future events. Perhaps the most important lessons from the 2009 H1N1 response reveal the complexity of coordinating actions among the many different actors, institutions, sectors, and disciplines involved in the public health system. While the response to the pandemic engendered creative "on the spot" solutions, continued effort is needed to better understand and manage the identified challenges. Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins.