What is the term for the personnel, bases, and activities that support the Marine Corps' operating forces?

The term that describes the personnel, bases, and activities that support the Marine Corps' operating forces is the Supporting Establishment. This encompasses a variety of non-combat entities that provide essential services such as training, maintenance, logistics, and administrative support, which are critical for the operational readiness of the Marine Corps.

The Supporting Establishment plays a pivotal role in ensuring that the operating forces, which are the units that engage directly in combat and other missions, have everything they need to function effectively. This includes maintaining equipment, supplying operational units with necessary resources, and providing training and administrative support.

Understanding this concept is important because it illustrates the relationship between operational and supporting forces within the Marine Corps, emphasizing that successful missions are facilitated by a robust support structure.