This United States Marine Corps USMC manual, Marine Corps Reference Publication MCRP 12-10A.1 Small-Unit Leader’s Guide to Mountain Warfare May 2026, is a reference for Marine leaders (team through company) to use when conducting operations in mountainous terrain, snow, cold weather, and at high altitudes. This publication is to be used in conjunction with the Marine Corps Tactical Publication 12-10A, Mountain Warfare; MCRP 12-10A.2, Mountain Leader’s Guide to Winter Operations; and MCRP 12-10A.3, Mountain Leader’s Guide to Mountain Warfare Operations.

The series covers individual and small unit tactics, techniques, and procedures across applicable warfighting functions. Topics include the environment, specialized clothing and equipment, weapons considerations, patrolling considerations, route selection and navigation, basic avalanche hazard assessment and mitigation, crossing streams and ice, snowshoeing, winter camouflage, logistics, fire support, helicopter operations, and casualty evacuation.

Because of the rapid turnover in personnel, operational tempo, and the multitude of training commitments, the Marine Corps Mountain Warfare Training Center cannot train all Marines or units. In combat, Marines may need to learn through doctrinal references that are augmented with instruction from their unit’s qualified summer and winter mountain leaders and basic cold-weather advisors. This MCRP gives them that capability.