where's turtle island? (for visitors from a2k confused about my whereabouts)

Turtle Island is the native american name for North America before the arrival of europeans. I first became aware of this while reading about the Turtle Island Quartet, a string quartet with an unconventional repertoire. I have seen a2k posts from a transexual taking up a lakota lifestyle after having been a vietnam vet, who also gave Turtle Island as her location. I tried to contact her, but the email address & url address she provided are no longer in service.