Here's a comprehensive list by state of the liquor laws.
BTW, I used to bartend in Ohio near the University of Cincinnati. Back then, beer was either less than 3.2% alcohol or more than 3.2% and less than 6% alcohol. 3.2% if you were 18 but under 21 and 6% if you were over 21. In practice, 3.2% was pretty close to that number, but 6% only had to be more than 3.2% and less than 6%. In practice, 6% was a lot closer to 3.2%. If you got caught by liquor agents, the bar paid the penalty, not the student, and the students knew it. We spent more time watching for students passing drinks than we did pouring them.