In the United States Navy, the expeditionary strike group (ESG) is a coordinated group of surface ships, aircraft, submarines, and other naval assets. In contrast to carrier strike groups (CSGs), which emphasize air power and are led by a supercarrier, ESGs are strongly suited for amphibious warfare and are led by an amphibious assault ship (currently of the Wasp or America classes). The ESG concept was introduced in the early 1990s, based on the Naval Expeditionary Task Force. The U.S. Navy fields nine expeditionary strike groups.
The ESG concept combines the capabilities of surface action groups, submarines, and maritime patrol aircraft with those of amphibious ready groups (ARGs) and Marine expeditionary units (MEUs) (special operations capable) to provide greater combat capabilities to theater combatant commanders.[1] An expeditionary strike force (ESF) integrates the CSG and ESG with the sea-basing functions provided by the maritime prepositioning force (future) to provide an even more potent capability.