Nicknamed the "Dirty Dozen", the Twelfth Brigade of the STARFLEET Marine Corps, or 12th BDE, is the administrative headquarters for all members of the SFMC and the units within the following states: Arkansas, Illinois, Kansas, Missouri, and Oklahoma. Each state within this geographical area are known as Battalions, or BTN. Disignated by alphabetical order, they are comprised of the First through Fifth of the Twelfth.

• Arkansas - First Battalion
• Illinois - Second Battalion
• Kansas - Third Battalion
• Missouri - Fourth Battalion
• Oklahoma - Fifth Battalion

Within each battalion are units that are assigned aboard ships, known as Marine Strike Groups or MSG, and non-assigned units, known as Marine Exploratory Units or MEU. Within Twelfth Brigade, there are the following active units:

Arkansas

• 245 MSG "Emperor's Guard", USS Sun-Tzu
• 275 MSG "Diamond Cutters", USS Blackstone

Illinois:

• 225 MSG "DedEx", USS Bortas
• 229 MSG "The Hunters", USS Orion
• 263 MSG "The Hawk's Talons", USS Black Hawk

Kansas

• 222 MSG "Madd Dogs", USS Jeannette Maddox
• 250 MSG "The Berserkers", ISS Olympus
• 269 MSG "The Black Bettys", USS Dark Phoenix

Missouri

• 201 MSG "The Fighting Wolfpack", USS Horizon
• 213 MSG "Umiak Targs", USS Umiak

Oklahoma 

• 234 MSG "Stray Dogs". USS Oklahoma
• 243 MSG "The Inglorious Gorn", USS Archangel
• 280 MSG "Buffalo Storm Wardens, USS Alan Turing
• 299 MSG "Infinite Dragon", USS Ouroboros

The current staff of the Twelfth Brigade is as follows:

• Brigade Officer in Charge - MGEN Dustin Williams
• Brigade Deputy Officer in Charge - COL Yolonda Whitworth
• Brigade Administrations Officer/S1 - MGEN S.C. Boggs
• Brigade Operations Officer/S2 - LT Jason Smith
• Brigade Communications/S3 - MCPT Aaron Morphew
• Brigade Awards Officer - FADM Les Rickard
• Events Coordinator/S4 - COL Yolonda Whitworth