text: Chapter 3
  CONTIGUOUS AREA OF OPERATIONS
  3-4. In most operations, corps and divisions employ contiguous areas of operations. Contiguous area of
  operations is where all of a commander’s subordinate forces’ areas of operations share one or more common
  boundaries (FM 3-90.1). This allows the command and control for the majority of the AO by using
  subordinate organizations while avoiding gaps and seams in responsibility. Contiguous areas of operations
  may provide additional security for maneuver units, headquarters, and support areas by limiting the gaps
  between units. Figure 3-1 provides an example of a contiguous corps AO with established support areas that
  include ground LOC.
  Legend:
  CSA corps support area
  DSA division support area
  SUST sustainment
  FSCL fire support coordination line
  Figure 3-1. Corps contiguous AO
  NONCONTIGUOUS AREA OF OPERATIONS
  3-5. A noncontiguous area of operations is where one or more of the commander’s subordinate force’s
  areas of operation do not share a common boundary (FM 3-90.1). The reasons for using a noncontiguous area
  vary but begin with geographical separation of important terrain from the remainder of the areas of
  operations. The commander’s decision deploys the force into a noncontiguous AO, regardless of command
  echelon, derived from the mission variables of METT-TC analysis. In particular, the commander evaluates
  the threat and ability of the enemy to mass combat power sufficient to threaten friendly forces in
  noncontiguous AOs. Second, the commander evaluates the enemy’s ability to sever ground LOCs between
  noncontiguous AOs.
  3-6. When conducting operations in a noncontiguous AO, commanders should take a holistic approach to
  countering threats. Commanders and staffs must expect the enemy to operate between the noncontiguous
  AOs using sophisticated surveillance devices, improvised explosive devices, mortars, rockets, missiles,
  unmanned aircraft systems, space and cyberspace operations, and information warfare, making support areas
  increasingly vulnerable. Area security may be the predominant method of protecting support areas that are