four-star admiral
The rank of admiral (or full admiral, or four-star admiral) is the highest rank normally achievable in the United States Navy. It ranks above vice admiral (three-star admiral) and below fleet admiral (five-star admiral).
There have been 279 four-star admirals in the history of the U.S. Navy. Of these, 238 achieved that rank while on active duty, 40 were promoted upon retirement in recognition of combat citations, and one was promoted posthumously. Admirals entered the Navy via several paths: 238 were commissioned via the U.S. Naval Academy (USNA), 25 via Naval Reserve Officers Training Corps (NROTC), nine via Officer Candidate School (OCS), two via warrant, two via Aviation Officer Candidate School (AOCS), one via direct commission (direct), one via the Naval Aviation Cadet (NAVCAD) program, and one via the U.S. Merchant Marine.