Abstract: The next generation of information systems for emergency management will be based on information provided by large and diverse collections of sensors, including information supplied by human volunteers. Consequently there is more than ever a need to provide solutions to the integration question, so that the Common Operating Picture can truly and effectively provide the unified view required of it. This paper describes some work on the ontology of information that can contribute to a solution of the integration problem. To set the stage, the paper discusses the relevance of information integration to emergency management, and then goes on to describe a project that provided the catalyst for this work. Later sections introduce ontological research and proceed to use it to lay the foundations for an ontology of information. In the final sections we indicate how such an ontology can be used in the context of emergency management.