US Army acronym for Mobile Army Surgical Hospital.
These are rapid-deployment hospitals to be used in the perimiter of conflict areas. In NATO, a large responsibility for deploying and maintaining MASH units rests upon the Norwegian army and air force. The tent-based system from the TV series M*A*S*H is outdated. The Norwegian Air Force uses container based systems that hook up to each other, forming a true indoor facility. These containers provide a surgical-standard clean room, are ABC resistant and highly mobile. A MASH unit can be established in one day, provided a good flat area is available.
A typical MASH unit has two operating theatres, a 40-bed recovery area, sanitary facilities, generator unit, clean water units, storage unit, administrative and personell units. There are no chow areas, these hospitals are so near combat that everyone eats MREs.
Perimiter defense is maintained by standard army personel, but usually MASH units are out of range for the enemy artillery and mortars so no other defense than armed guards is necessary. In a hot situation, medical personell will carry SSG or MP5.
Transportation of units can be done via helicopter or truck, assembly is done with mobile crane and is the responsiility of the engineer corps.