Purpose: This regulation establishes the required structure and mission of each U.S. Army Corps of Engineers (USACE), Major Subordinate Command (MSC), and Headquarters (HQ); and describes how each MSC Commander will manage subordinate organizations via a regional business construct. The organizations that make up each region (collectively referred to as the Regional Business Center) include the MSC HQ, and its subordinate districts. Successful operation of the region necessitates regional interdependence augmented by technical support from other RBC’s and USACE centers of expertise.