The Narita Mountains (成田山 Naritayama) are a mountainous region originally occupied by the Japan Liberation Front as a major base.
After being discovered by the Holy Britannian Empire as the HQ of the JLF, it becomes the site of an armed skirmish between Cornelia and the JLF. However, they are interrupted by the Black Knights who use the Guren Mk-II to create a landslide. The resulting landslide wipes out a fair portion of both Cornelia's forces and the JLF's, and also damages the small settlement of Narita downhill, killing many civilians. Among the dead is Shirley's father, Joseph Fenette, a Britannian public official who was surveying the region for veins of sakuradite; in the novels, he is said to be an associate of General Bartley. A memorial to the Britannian citizens who lost their lives in the incident was later built in the area. One of the laboratories of the Rosenberg Institute used by Bartley to research C.C. was situated in the town until the above events forced a relocation. Neither the settlement nor the mountain range by the same name bear any relationship with the actual Narita City.