Do I need a passport to travel from the U.S. to Mexico, or to travel back into the U.S. by car?

I will be traveling to Mexico next week, but I heard that we need a passport when traveling by airplane. Is this true when traveling by ground?

You need a passport.

yup

yes

Yes you do need a passport.

yes

I did not need a passport when I drove to Mexico from California about five years ago.

Yes.

Yup! New US policy, even on a cruise around the bay, if you leave US shores you need a passport to get back in.

Yes, after Jan 1st you need a passport for both Mexico/US and Canada/US travel, no matter which way you travel--planes, trains, automobiles, etc.