where did judiasm originate?

Answer 1

Most people believe it originated with Abraham -- see Genesis.

http://wiki.answers.com/Q/How_did_Judaism_start

Answer 2

Could it be Judea?

Answer 3

Be sure to read the first paragraph carefully. Then check out the maps among these:
http://www.google.com/search?q=map+mesopotamia&rls=com.microsoft:en-us:IE-SearchBox&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7SUNA