Starfleet Command was the operating authority of Starfleet and, before that, Earth Starfleet. Its headquarters were located in San Francisco on Earth. Starfleet Academy was also located in the same area in San Francisco.
There was at least one additional office of Starfleet Command which was located in Chicago. Commander-in-Chief Thomas Crowe was known to prefer his office in Chicago, as he liked the cold weather. (Star Trek: Remington)
Rivalries and outright "turf wars" between divisions such as Starfleet Intelligence and Starfleet Security often went on, unbeknownst to the general public and to most Starfleet personnel. Such a rivalry was known as a "Big Game". (Cloak and Dagger)
There also existed a Starfleet Command in the Lyran Starfleet; the term Clan Elders was also used to designate Starfleet Command among Lyrans. Akeelah, after her demotion, mistakenly referred to Starfleet Command as Stonefleet Command. (Star Trek: The Stoneship Files: "Highly Illogical")
|The Branches of Starfleet|
|Earth Starfleet: Command | Medical | Security | Section 31 | Training Command|
|Federation Starfleet: Administration | Administrative Operations | Advanced Technologies | Command | Communications | Control | Dental | Engineering Corps | Exploratory Division | Information | Intelligence | Internal Affairs | Judge Advocate General | Medical | Mission Operations | Operations | Orbital Operations | OSHC | Research and Development | Science | Section 31 | Security | Shipyards Operations | Stellar Imaging | Tactical | Training Command | Warp Technologies|