Transhumance is a type of pastoralism or nomadism, a seasonal movement of livestock between fixed summer and winter pastures. In montane regions (vertical transhumance), it implies movement between higher pastures in summer and lower valleys in winter. Herders have a permanent home, typically in valleys. Generally only the herds travel, with a certain number of people necessary to tend them, while the main population stays at the base. In contrast, horizontal transhumance is more susceptible to being disrupted by climatic, economic, or political change.
Traditional or fixed transhumance has occurred throughout the inhabited world, particularly Europe and western Asia. It is often important to pastoralist societies, as the dairy products of transhumance flocks and herds (milk, butter, yogurt and cheese) may form much of the diet of such populations. In many languages there are words for the higher summer pastures, and frequently these words have been used as place names: e.g. hafod in Wales and shieling in Scotland.