Passport needed for Mexico

Casinojunkie wrote:
I am a United States citizen and
wish to go into Mexico next week.
Just across the boarder into Progreso
Do I need a passport or is there other documents that will be acceptable to get back into the United States.
Not enough time to get passport.
Thanks to all

There's no excuse for not following the established rules - since beginning of 2008.
travel.state.gov

You can get a passport in one day provided you have the necessary documents (birth cert, ss card). Make an appointment and pay for it.
Issued same day or next day.