 Anyone who is under the age of 21 and possesses alcohol in the United States, with the exception of special circumstances, is violating the law of the state.The term "Minor in Possession" is a misnomer, because Americans between 18 and 20 years old are not minors but legal adults, except for residents of Mississippi and 18-year-old residents of Alabama and Nebraska.Punishments for minors in possession vary greatly from state-to-state.