To test local, state, regional, military, and federal response and recovery preparedness activities, Vigilant Guard New York 2009 (VGNY) simulated response to a 5.9 Richter scale earthquake hitting the Buffalo, Niagara Falls, and Erie County regions of New York. Working closely with Erie County and the New York State Emergency Management Office, we developed a Homeland Security Exercise and Evaluation Program (HSEEP)-compliant functional exercise that focused on coordination of response activities, establishment of a common operating picture, examination of mutual aid doctrine, and assessment of collaborative capabilities between all participating entities. VGNY 2009 began with a tabletop exercise that simulated the initial 48 hours of the earthquake response. The four day functional exercise began at hour 49 and was customized based upon results of the tabletop exercise.