This article proposes an economic activity location model centred on the principle of sustainability. For this purpose the environment is considered in an ample sense, encompassing tangible and intangible components and their dynamics.This requires the use of the social entropy concept. The decision to insert a project into the environment generates a sequence of two-way effects,i.e., a long-term trajectory that is subject to a number of other decisions. A sustainable location decisionis the project-site combination that causes the lesser increase in socialentropy.The proposed model identifies the relevant variables and their relationships. It alsoindicates simulation and fuzzy logic to handle different technological paths, different sets of public and private investments, and changes in regulation. Despite the model is obviously not exact, it offers valuable information to public and private actors, so they can negotiate on a nearly objective basis.Finally, the model shows how to effectively enable decision makers to pursue sustainability