I am a Turkish citizen holding a ten year US tourist visa. I spent six months (the legal time alloted to me) in the US with a B-1/B-2 visa, and am now in Mexico. I have heard that traveing to Mexico does not count as leaving the US and that if I try to reenter the US after six months I will not be allowed reentry. Is this true? Does anyone have experience with this?
Going to Mexico does count as leaving the US. There is some concern about using Mexico for visa runs (short trips for the purpose of renewing your period of admission), and there are statutory rules in place to prevent the "resetting" of the period of admission by traveling to Mexico or other "adjacent territories," but these concern the visa waiver program travelers, not visa holders. If you return to the US after six months in Mexico, visa runs will not be a concern.