"De facto" wilderness refers to places that meet the minimum criteria for being part of the National Wilderness Preservation System, but which have not been added to the system. Some of these areas may be slated for development, some may have partial protection through administrative and congressional measures. Many just slowly get "nicked", "dirt-biked", and their wilderness character fades away. Twenty years later "old-timers" tell stories about elk they used to see or hunt and how the rivers were "red" with salmon.
The criteria for being added to the NWPS are: