What is the highest rank in the Navy indicated by the O-10 pay grade?

The highest rank in the Navy indicated by the O-10 pay grade is Admiral. The O-10 pay grade is reserved for the most senior officers in the Navy, specifically reflecting the rank of Admiral. In the Navy, an Admiral is a four-star officer, representing the pinnacle of naval leadership and responsibility.

To provide additional context, the other ranks listed fall below O-10. Rear Admiral (lower half) is categorized as O-7, while Rear Admiral (upper half) is O-8, and Vice Admiral is O-9. Each of these ranks entails significant leadership roles, but they do not achieve the highest level represented by the O-10 designation. Therefore, Admiral is recognized as the highest achievable rank in the Navy, signifying a position of great authority and command over large naval operations or flanks.