Mount Kawayama (妙川山, Myōkawayama, literally Mysterious/Exquisite River Mountain) is the land of Monkeys, the place where all the monkeys that Jūbei summons live. It is home for huge and small Monkeys and apes alike. Mount Kawayama is a rich and beautiful land.
For a human to get to Mount Kawayama, if they have a summoning contract, they can let a monkey use the Reverse Summoning Technique. Jubei was transported to Mount Kawayama in his youth via using the summoning technique without a contract.
Some of the inhabitants of Mount Kawayama can use senjutsu, to gather natural energy. There is a sacred tree there like the oil fountain at Mount Myōboku which produces a special sap that allows people to more easily feel the natural energy around them, but if the person is not perfectly still, becoming one with nature, he or she starts becoming a monkey and eventually turns into stone. This sap can only exist in the atmosphere of the mountain, and will evaporate if taken outside. There are many statues of the mankey and ape ancestors and of people who tried to learn senjutsu, but failed and became statues. The statues are treated with much respect.
The current king of Kawayama is Goku. Though he is the leader of all the monkeys and apes in Kawayama, the Elder Council is held in even higher regard. They are the spiritual leaders of Kawayama. All members of the council have mastered senjutsu and are very wise and venerable beings. There are currently four members in the Council; the former Monkey King Enma, Mizaru, Kikazaru, and Iwazaru. Another monkey by the name of Shizaru is also capable of using senjutsu but is not a member of the council due to his relative youth and inexperience. All the members of the council except Enma are physically very small in stature, as is Shizaru. Thus any one of them can be summoned by Jubei to perform Sage Art: Mammalian Technique to fuse with them to use Sage Mode.