Are Sheol, Hades, and Gehenna the same?

They should not be treated as automatic synonyms. Sheol is Hebrew vocabulary associated with the dead or grave in varied Old Testament contexts. Hades is Greek vocabulary connected with the realm of the dead; Revelation 20 distinguishes it from the lake of fire. Gehenna appears in Jesus’ warnings about judgment and carries associations with the Valley of Hinnom. Translation into one English word can obscure these differences. Context, genre, and the actual subjects of a passage matter. A vocabulary distinction does not by itself produce a complete map of the afterlife, nor can it certify a modern vision’s claimed location.