This Army tactics, techniques, and procedures (ATTP)/Marine Corps reference publication (MCRP) is the Army’s doctrinal publication for operations in the cold region environment. Marines can utilize this publication as an operational reference with the 3-35 doctrinal series. It provides doctrinal guidance and direction for how United States (U.S.) forces conduct cold region operations. The purpose of ATTP 3-97.11/MCRP 3-35.1D is to arm leaders, Soldiers, and Marines with the necessary knowledge on how to operate in cold region environments. The information contained in this manual applies to all Soldiers and Marines, regardless of rank or job specialty. This manual is designed to work with and complement field manual (FM) 3-97.6, Mountain Operations, and FM 3-97.61, Military Mountaineering. This manual will enable leaders, Soldiers, and Marines to accurately describe cold region environments, their effects on military equipment, impacts these environments have on personnel, and most importantly, how to employ the elements of combat power in cold region environments.