We are not able to locate this abyss in a geographical manner. That is no surprise, for we cannot locate heaven as a geographical place either (other than to say that it is “up”). The Lord God, Creator of time and space, is not bound by our limitations of “here” or “there.” It is enough to say that this abyss is “down,” namely, as far away from God (“up”) as possible.
1 And the fifth angel blew his trumpet, and I saw a star fallen from heaven to earth, and he was given the key to the shaft of the bottomless pit.