The use of forests for recreation is increasing. For many people, outdoor recreation involves direct contact with forests in various activities ranging from walking in the woods to wilderness backpacking. The primary suppliers of forest recreation opportunities in the United States are federal land management agencies such as the U.S. Department of Agriculture (USDA) Forest Service, the National Park Service, and the Bureau of Land Management; state recreation, park, wildlife, and forest departments; and private landowners and corporations (ski areas, industrial forests, resorts). The federal land management agencies administer over 650 million acres (265 million hectares) open for outdoor recreation, while there are more than 11 million acres (4.5 million hectares) of state lands and over 180 million acres (73 million hectares) of private lands open or leased for outdoor recreation.