Emergency management is more than just events occurring within an emergency situation. It encompasses a variety of persistent activities such as planning, training, assessment, and organizational change. We are studying emergency management planning practices in which geographic communities (towns and regions) prepare to respond efficiently to significant emergency events. Community emergency management planning is an extensive collaboration involving numerous stakeholders throughout the community and both reflecting and challenging the community’s structure and resources. Geocollaboration is one aspect of the effort. Emergency managers, public works directors, first responders, and local transportation managers need to exchange information relating to possible emergency event locations and their surrounding areas. They need to examine geospatial maps together and collaboratively develop emergency plans and procedures. Issues such as emergency vehicle traffic routes and staging areas for command posts, arriving media, and personal first responders’ vehicles must be agreed upon prior to an emergency event to ensure an efficient and effective response. This work presents a software architecture that facilitates the development of geocollaboration solutions. The architecture extends prior geocollaboration research and reuses existing geospatial information models. Emergency management planning is one application domain for the architecture. Geocollaboration tools can be developed that support community-wide emergency management planning and preparedness. This paper describes how the software architecture can be used for the geospatial, emergency management planning activities of one community.