Wilderness and backcountry are not interchangeable terms, but more often than not they are overlapping terms, for much of our wilderness areas are considered part of the backcountry and vice versa. Wilderness is more of a biological description that describes large tracts of land where the natural process of plant growth and animal activity is unhindered by the presence of man. On the other hand, backcountry refers to places that are remote and inaccessible, but not necessarily pristine in nature. For example, grazing by livestock is allowed on many places in our national forests. These places might be classified as part of the backcountry, but they would not be classified as true wilderness, even when situated high in the Rocky Mountains or the Sierra Nevada.
Hinterlands and outback are two words that are nearly synonymous with backcountry. Again, these words express the inaccessible nature of these isolated, rural areas that we call the backcountry. Implicit in the definition is the concept that anybody can visit these wild places and that transportation in these places is either human-powered or at least non-motorized.
In the United States much of the backcountry falls under the jurisdiction of government entities. The federal government is the most common caretaker of backcountry areas, but state or local governments have oversight on some public lands. These government bodies are in essence charged with the task of defining how the land is used, and subsequently, how the place would be defined. Generally speaking, motorized transportation is not part of the backcountry experience, with the possible exception of snowmobile travel in winter.
Private owners rarely allow public use of their lands, but sometimes they do allow public passage across their property. This is most evident in some of the longer trail systems that exist in this country, most notably the Appalachian Trail and Pacific Crest Trail. The Appalachian is a continuous hiking path that goes from Georgia to Maine. It is made possible by the many landowners along the way, who during the early years of the trail, allowed passage through their property (hikers can't venture off the trail). However, in 1968 the federal government declared the Appalachian Trail under federal jurisdiction, a complicated situation, which created a thin corridor of land along the trail that now comes under federal regulation.
Backcountry is frequently used when describing an outdoor activity, such as hiking, skiing or canoeing, which is served by few amenities and requires advanced skills. In some cases, especially skiing, backcountry is not only used to determine where the activity takes place, but also to imply methods and techniques. For example, a skier who insists on walking to the top of a ski slope and then skiing to the bottom on a pair of mountaineering skis could be considered a backcountry skier, even if he or she is skiing on a trail that is serviced by a modern ski lift.