This report offers a multi-disciplinary perspective on the cybersecurity industry. Conceptualizing cybersecurity industry clusters as ecosystems, we focus on three distinct mega-clusters: the San Francisco Bay Area, metropolitan Washington, D.C., and Israel. Benefits of clustering include: access to a pool of specialized labor, knowledge spillover, access to capital, and inter-organizational linkages. Research suggests that clusters’ economics should be linked to their social dimensions and the configuration of the built environment. In addition, based on the empirical analysis, we suggest using a nuanced taxonomy of cybersecurity clusters using a spectrum of intensities: mega-, mesa- and micro-clusters, sub-clusters, and hot zones.