Tables and computation methods for evaluating the load that can be carried by porters under various conditions. The logistic importance of porterage has been a disputed issue in American military planning. This study shows quantitatively its value in such areas as Thailand and Vietnam, and its costliness and inefficiency in areas of jungle and mountain. Data were drawn from specific historical accounts, mostly unclassified data from classified RAND publications. The most detailed information is from United Nations and North Korean experience in the Korean conflict, the Viet Minh planning factors in Indochina, and the 1963 American expedition up Mt. Everest. Weight carried and daily travel distance were related to the geographic, military, and physical conditions. Average ton-miles per man/day range from .04 to .21 and speed varies from 1.8 to 3 mph, depending on terrain, illumination, etc. Methods of estimating trail capacity and the probability of observation are given, and different staging policies are evaluated.