Wilderness areas are federally-owned public lands managed by the federal government through four agencies, the Bureau of Land Management, Fish and Wildlife Service, Forest Service, and National Park Service. When the National Wilderness Preservation System started in 1964, only 54 wilderness areas were included. Since then, the system has grown nearly every year to include more than 800. The time component of this service is based on the year in which the wilderness was originally designated (additions may have occurred in subsequent years). Overall, however, only about 5% of the entire United States—an area slightly larger than the state of California— is protected as wilderness. Because Alaska contains just over half of America's wilderness, only about 2.7% of the contiguous United States—an area about the size of Minnesota—is protected as wilderness. To learn more about wilderness areas, visit Wilderness Connect, the authoritative source for wilderness information online. Wilderness Connect also publishes two other map resources:

• An interactive wilderness map allows visitors to search for and explore all wilderness areas in the United States. 
• Fact-filled storymaps on the benefits of wilderness illustrate how wilderness protects values including clean water, wildlife habitat, nearby recreation, cultural sites and more.

Although wilderness areas are federally-owned, some areas contain non-federal parcels within their boundaries. Non-federal lands within some wilderness areas are included as part of this feature dataset as a separate layer. Termed inholdings or edgeholdings, these lands are privately-owned or owned by local governments, state governments or Indigenous Nations. Hundreds of inholdings and edgeholdings exist across the wilderness system. Generally, however, they are small compared to the size of the wilderness itself. Since the rules and regulations that apply to wilderness areas do not apply to these non-federally-owned parcels, it is important for wilderness visitors to know their location to avoid trespassing where access is not allowed. The owners of inholdings and edgeholdings can develop these parcels (as long as developments do not affect the character of the surrounding wilderness lands) and they retain special and limited access to them, sometimes, but not always, by motorized means.