USS Essex (CV/CVA/CVS-9) was an aircraft carrier and the lead ship of the 24-ship Essex class built for the United States Navy during World War II. She was the fourth US Navy ship to bear the name. Commissioned in December 1942, Essex participated in several campaigns in the Pacific Theater of Operations, earning the Presidential Unit Citation and 13 battle stars. Decommissioned shortly after the end of the war, she was modernized and recommissioned in the early 1950s as an attack carrier (CVA), eventually becoming an antisubmarine aircraft carrier (CVS). In her second career, she served mainly in the Atlantic, playing a role in the Cuban Missile Crisis. She also participated in the Korean War, earning four battle stars and the Navy Unit Commendation. She was the primary recovery carrier for the Apollo 7 space mission.

The Essex class is a retired class of aircraft carriers of the United States Navy. The 20th century's most numerous class of capital ship, the class consisted of 24 vessels, which came in "short-hull" and "long-hull" versions. Thirty-two ships were ordered, but as World War II wound down, six were canceled before construction, and two were canceled after construction had begun. Fourteen saw combat during World War II. None were lost to enemy action, though several sustained crippling damage due to kamikaze attacks. Essex-class carriers were the backbone of the U.S. Navy from mid-1943 and, with the three Midway-class carriers added just after the war, continued to be the heart of U.S. naval strength until supercarriers joined the fleet in the 1950s, 1960s and 1970s. Several of the carriers were rebuilt to handle heavier and faster aircraft of the early jet age, and some served until well after the Vietnam War. Of the 24 ships in the class, four of the carriers: Yorktown, Hornet, Lexington, and Intrepid, have been preserved as museum ships.