Hill farming is extensive farming in upland areas, primarily rearing sheep, although historically cattle were often reared extensively in upland areas. Hill farming is a type of agricultural practice in the UK in upland regions. In England, hill farms are located mainly in the North and South-Western regions, as well as a few areas bordering Wales. The Scottish highlands are another home for many hill farms. Sheep farms and mixed sheep and cattle farms constitute approximately 55% of the agricultural land in Scotland. These areas have a harsh climate, short growing seasons, relatively poor quality of soil and long winters. Therefore, these areas are considered to be disadvantaged and the animals raised there are generally less productive and farmers will often send them down to the lowlands to be fattened up. Upland areas are not traditionally favorable for agricultural practices. Sustainable farming systems in upland areas are one of the greatest challenges facing agriculture, since a balance is sought between economic development and environmental protection in those areas. Uplands are particularly sensitive to agricultural encroachments. Driven by growing food demand to feed increasing populations and low farm income in many uplands, however, there is a tendency to use more productive, intensive farming methods in place of traditional subsistence farming characterized by poor crop yields and low farm productivity. Intensive farming methods suitable for lowlands can be disastrous when used on uplands without proven technologies and experience, promoting deforestation and soil erosion and reducing land productivity. The problem of sustainable upland agriculture is not a technical one as such but it is more institutional, involving limited R&D investment in upland farming research, sociopolitical neglect of marginalized upland societies, low capacity of communities, and inappropriate development planning. In recent years, there have been some successful examples of sustainable upland farming. Farmers need cash crops as well as food crops, in systems which maintain soil productivity. Where transport networks are poor, low-volume high-value cash crops with a long storage life are important. Many farming households now earn a living from direct marketing of specialty crops and animals, accommodation, or recreation and leisure, as well as farming.