What does a citzen minor need when they come back from Mexico?

A U.S. citizen minor (under the age of 18) needs a valid U.S. passport to enter the United States from Mexico. If the minor does not have a valid U.S. passport, they may be able to enter the United States with a birth certificate and a photo ID, such as a school ID or driver's license. However, it is strongly recommended that all U.S. citizens, including minors, carry a valid U.S. passport when traveling abroad.