pocket wilderness
n.— «Jordan Linger, 21, and John Lockley, 19, both of Fort Oglethorpe had been reported missing about midnight Thursday after they didn’t return from a day hike in an area known as the “pocket wilderness” on Mowbray Mountain.» —“Hikers emerge from wilderness unharmed” by Chattanooga, Tennessee Athens Banner-Herald (Georgia) Jan. 6, 2007. (source: Double-Tongued Dictionary)