Dharma Data: Hell
He lowest and most fearful of the Realms of Existence. In many discourses the Buddha describes hell as an actual place while in others he seems to suggest that it is only a name for the experience of extreme suffering. He says "When the average ignorant person says that hell is under the sea, he is saying something that is false and without basis, the word hell is a name for painful feeling". The Buddhist conception of hell differs considerably from those of some other religions. There is no divine judge to condemn one to hell, rather one's own evil Kamma gives rise to rebirth in this realm. Re-birth in hell is determined by one's actions not primarily by one's beliefs. Thus no good person no matter what their religion will be re-born in hell. Hell is not eternal and when one's lifespan there is finished one will be re-born in one of the other realms.
B.C. Law, Heaven and Hell in Buddhist Perspective. Varanasi, 1973.