I’ve been ten thousand miles in the mouth of a graveyard

from Bob Dylan – A Hard Rain's a-Gonna Fall Lyrics on Rap Genius

From sea to sea, there is 3300 miles across the USA. If you combine the land masses of Europe and Asia, etc. it would be, poetically speaking, about 10,000 miles.

He’s saying that there is nothing but bodies lying dead everywhere in the world.

“Rev 6:8 And I looked, and behold a pale horse: and his name that sat on him was Death, and Hell followed with him. And power was given unto them over the fourth part of the earth, to kill with sword, and with hunger, and with death, and with the beasts of the earth. ”

To help improve the meaning of these lyrics, visit "A Hard Rain's a-Gonna Fall" by Bob Dylan Lyrics and leave a comment on the lyrics box