The Civil Irregular Defense Group (CIDG) was a US Sponsored local milita organization 
created in South Vietnam.  The purpose of the CIDGs were to provide protection for so-called 
"fortified hamlets" and special force camps, as well as, to harass the Viet Cong and patrol 
the countryside.  Originally a Central Intelligence Agency sponsored project, control
was passed to Military Assistance Command Vietnam during Operation Switchback in 1963.
These units operated more or less under direct US control until the end of 1970 when they
were transfered to the Army of the Republic of Vietnam.
*
When this transfer occured, the CIDG elements were converted into new Ranger Border Defense Battalions.
The animosity between low-land ethnic Vietnamese and the various highland mountain tribes
of Vietnam meant that the capability of RBD units was questionable at best, because of an unwillingness
to fight for their new Vietnamese leaders.
*
Organizations provided here are approximations based on
available evidence.