Marine Security Guards (MSG) are responsible for the Security of the United States Embassies and Consulates thru out the World. They trained at Quantico Virginia and assigned to Security Guard Bn when posted to a particular Embassey/ Consulate they will be assigned to an MSG Detachment That MSG Detachment is assigned to one of the MSG Companies A-H within the MSG Bn. Such as MSG Det Lima Peru, Co. D (Ft Lauderdale Fl.) MSG Bn. Companies are based on Geographic Location and contain all Embassies within that area. MSG Companies are commanded by Lt. Col's and contain the all the Administrative staff for those Detachments.
MSG Detachments are commanded by ethier a Commissioned Officer Or SNCOS (Ssgt, Gysgt, Msgt or Mgyst) depending on the Mission. Detchment Commanders are responsible for the Operational Deployment of the the MSG DET and work with the Mission RSO (Regional Security Officer) to form the Post Security Team.
The size of the Detachment is dictated by many things including Size of mission, security threat etc, no Detachment is smaller than 1 and 5 for a 1 post mission.
MSG Duty is two 15 month tours with some Missions designated 12 month hardship tours. Only Detachment Commanders may be Married while assigned to MSG Duty.
MSG training is conducted at the MSG School and is 6 weeks for Sgt. and below, 8 Weeks for Ssgt and above. It has the highest drop rate of the Marine Corps Schools.