Ancestry pegs Kurt Cobain as my 9th cousin, once removed through our MRCA, Josiah Thayer (1670-1728). Josiah would be my 8th great grandfather! To date, I can only document through to my 4th great grandmother, Esther Clark, in that particular line. So, 4 generations to verify! But, according to Ancestry, also sharing Josiah as a MRCA, are Sarah Palin, Eddie Cochran, and Jim Morrison.