A precondition for assessing mission resilience in a cyber context is identifying which cyber assets support the mission. However, determining the asset dependencies of a mission is typically a manual process that is time consuming, labor intensive and error-prone. Automating the process of mapping between network assets and organizational missions is highly desirable but technically challenging because it is difficult to find an appropriate proxy within available cyber data for an asset's mission utilization. In this paper we discuss strategies to automate the processes of both breaking an organization into its constituent mission areas, and mapping those mission areas onto network assets, using a data-driven approach. We have implemented these strategies to mine network data at MIT Lincoln Laboratory, and provide examples. We also discuss examples of how such mission mapping tools can help an analyst to identify patterns and develop contextual insight that would otherwise have been obscure.