The Mystic Mountains (or just Mystic Mountain) are a range of mountains southwest of Ioka and home to a Gate. Like much of the prehistoric world, they are overrun by dinosaurs and primitive monsters. The tribesman Kino is said to have been found as a baby on the top of the mountain, perhaps contributing to its name. On Crono's original visit to early history, the party was attacked by several Reptites. The ambush was fended off by Ayla, who happened to be in the area; subsequently, Mystic Mountain was utilized for its Gate, which could be accessed by jumping off a cliff.
A theory holds that Gaea's Navel has some kind of connection with Mystic Mountain. The reasoning goes that since Kino appeared at Mystic Mountain as a child before The Entity created the Gates, and that since Leah is similarly displaced in a land reminiscent of prehistory, a naturally occurring time distortion links to the two areas. However, this connection has no real basis other than that Leah declares she will name her child Ayla, which is probably just an easter egg left by the developers.