From Bravo Fleet Infobase
Section 31 is the code name of an officially nonexistent rogue agency that operates outside the purview of Starfleet Intelligence.
|Agengy's Governing Body:||Unknown|
|Agency's Role:||Intelligence gathering and Covert Operations|
|Agency Headquarter Location:||Unknown|
|Agency Head's Name:||Unknown|
|Agency Head Title:||Director|
|[ Source ]|
Section 31 exists outside Starfleet Intelligence's influence and deals with threats to Earth's and, later, the Federation's security.
Its operating authority stems from an obscure provision of the Starfleet charter — Article 14, Section 31, from which its name is derived — that makes allowances for "bending the rules" during times of extraordinary threats.
While the original intent may have been to give Starfleet personnel some leeway when it comes to unusual or extreme circumstances, some Federation Council and Starfleet officials have taken it a step further and secretly created a standing organization able to respond to any threat, preemptively if need be. Section 31 is similar to the Romulan Tal'Shiar or Cardassian Obsidian Order in that it operates covertly; unlike those organizations, however, Section 31 does not exist to punish traitors or enforce the will of the state (the Tal Shiar and Obsidian Order were greatly feared among their populaces. Instead, Section 31 claims to operate in the name of the security of the United Federation of Planets and to protect its interests throughout the galaxy.
Most Federation citizens have never heard of Section 31, or have even suspected of its existence.
Section 31 has no specific headquarters or even a base of operation. Very few, even within the organization, know for sure who commands the agency or how it is structured.
Deputy Director Sloan