Q: someone said 40 years old. hope not
A: The age to buy alcohol in all parts of the united states is 21. You probably heard that if you look under 40, you will have to produce proper identification. This can be a state drivers license or ID, a military ID, etc. If you look under 40 and can't produce proper ID, you will be denied the sale, regardless of whether you are 20 or 39.