The paper describes the ‘ physical system ’ theoretic construction developed to model the Canadian economy at a level of ten sectors in each of five regions, but which has general applicability. The national economy is identified here as a collection of interconnected components and the approach taken is that of component-to-system construction. It is believed that the framework is general enough to embrace many ‘ input-output’ models in oconomic literature. Specifically, specialization to a few selected models is demonstrated.