Gap of Calenardhon

This was known in the Second Age as the Calenhyarden, (S. "Green Southern Passage"). It became known after the 26th century ofthe Third Age as the Gap of Rohan. A purely lowland passage, it could be used freely as long as the Dunlendings of Dunfearan were not involved in either an internal or external war. In T.A. 1643, Gondorian patrols from Angrenost, the fortress at the southern end of the mountains centered around the tower of Orthanc,had protected the gap and patroled into Dunfearan as far as the watershed line between the valleys of the Dunstrem and the River Angren (Isen), within five days ride of Tharbad.