Board Thread:Questions and Answers/@comment-28096636-20170813022819/@comment-918732-20170815142506

This may be easy, but I had to look it up recently, so:

What is the lowest-numbered pre-Crisis alternate Earth that we know nothing about? We know what Earth-One is, and Earth-Two, etc. How far do we have to go to find an Earth that hasn't appeared in comics (yet)?