This level of architecture is defined in the common approach to Federal Enterprise Architecture Framework and includes all (Federal, State, Tribal, and Local) government agencies within a country (the U.S. and its territories).

These architectures are very important to the coordination of nation-wide capabilities, such as sustainable development, first-responder coordination, disaster notification, telecommunications, and transportation infrastructure.

Source: See Federal Enterprise Architecture Framework (common approach - as explained in Collaborative Planning Methodology).