What is the highest naval rank identified in the Navy from the provided information?

The highest naval rank identified within the U.S. Navy is Fleet Admiral. This position is a five-star flag officer rank, which is higher than both Admiral and Vice Admiral, and is typically reserved for wartime conditions or extraordinary scenarios, with very few individuals ever holding this rank. The last rank of Fleet Admiral was held by a select few during World War II, including notable figures like William D. Leahy and Chester W. Nimitz. As a rank, Fleet Admiral surpasses all other naval ranks, including Vice Admiral and Admiral, which are both four-star ranks, and Rear Admiral, which is a two- or three-star rank depending on its designation. Thus, Fleet Admiral stands as the pinnacle of naval rank and is specifically recognized for its limited and exceptional usage in the history of the U.S. Navy.