Emergency Operations Centers (EOCs) are locations from where activities are conducted in support of emergency incident response, including management of information flows/communications and coordination of strategic decision-making and activities across diverse communities and organizations. To date, knowledge is limited about practices involved in structuring and operating EOCs at public offices of emergency management (OEMs) and influencing factors. Through surveys and analysis of organizational documents, this study examines the models used by OEMs and the factors that influence the choice of models and organizational perception of the effectiveness of the employed models. Our results indicate that the emergency support function (ESF) model is the most commonly used, followed by a hybrid model, the incident command system model, and finally, the departmental structure and incident support model. We found no single model to be decisively superior; rather, different models are appropriate depending on personnel, resource availability, and the context of the jurisdiction. The ESF model, which is the most commonly utilized, appears to be difficult to employ effectively when organizations have limited access to trained personnel necessary for carrying out the range of functions specified in the model. In comparison, other models appear better suited to handle personnel constraints.