United States Navy (USN)

The naval service of the United States armed forces, the world’s largest navy by tonnage and the benchmark blue-water fleet. The USN is built around nuclear aircraft carriers (CVN) and their strike groups, guided-missile cruisers (CG) and destroyers (DDG) with the Aegis combat system and Mk 41 VLS, attack and ballistic-missile submarines (SSN, SSBN), and amphibious forces (LHA/LHD, LPD, LSD). It sustains forward presence through numbered fleets and underway replenishment, and frames its approach through documents such as A Cooperative Strategy for 21st Century Seapower.