Jigokudani, in which the park is located, means "hell valley" and is a common name for Japanese valleys with volcanic activity. The park has one man-made pool around which the monkeys gather, located a few minutes' walk from the park entrance. The monkeys live in large social groups, and it can be quite entertaining to watch their interactions. Accustomed to humans, the monkeys can be observed from very close and almost completely ignore their human guests.