As there are quite a few branches of the O'Cain family, not all related, it would help if you knew the names of any of your ancestors. My family is from Arkansas (can't find any links to other O'Cains in the South, yet) and several brothers went to California during the 1920s and 1930s. Their names were John Frederick O'Cain, Leo O'Cain, and John Dale O'Cain. For the most part they settled in Southern California around Los Angeles. I think that John Dale later moved to Arizona.