Passport:
Your passport is your own government's permit for you to leave and re-enter your own country. When you enter the United States your passport must be valid for a minimum of six months into the future. If your passport will expire during your time in the U.S. you must contact your Embassy for renewal procedures.
Visa:
A visa is used only for entry into the United States. It shows the latest dates on which you may enter this country. It does not show how long you can stay in the U.S.
If your visa will or has expired and you plan to travel outside the United States, contact the International Programs Office prior to your departure to make sure that you have proper documentation.
For the Mexican Embassy click Here

