January 31, 2008 - US Border Officials requires Passports or Birth Certificates for travel across the US Border.

As of Thursday, you'll be asked to prove your claims of being an American citizen when you return for a visit to Mexico.

New, stricter border crossing rules take effect at U.S. ports of entry at San Luis, Ariz., Andrade, Calif., and elsewhere along the nation's borders with Mexico and Canada.

Border crossers 19 and older will be required to produce proof of citizenship - either a U.S. or Canadian passport, or a birth certificate and government-issued identification, such as a driver's license or military ID.

Those 18 and under will be asked to provide a proof of citizenship, such as a passport or a birth certificate. The transitional period can take months until a passport or other acceptable document such as a passport card is required in June 2009.

Read this article which explains the new border rules