Where is the 4th fleet (SOUTHCOM) located?

The 4th Fleet, which is part of the United States Southern Command (SOUTHCOM), is indeed located at Mayport, Florida. This fleet is responsible for U.S. naval operations, including maritime security and humanitarian assistance, throughout the Caribbean, Central America, and South America. The strategic location in Mayport allows the 4th Fleet to effectively support U.S. interests in the southern region, coordinate exercises with partner nations, and respond to emerging threats or natural disasters in that area.

The other locations mentioned, such as Miami, San Diego, and Norfolk, are home to other naval fleets and commands. Each of these locations hosts distinct operational focuses that align with their geographic responsibilities, but the emphasis on the context of regional maritime operations is why Mayport is the correct choice for the 4th Fleet's location.