Where can I buy a burger in U.S.A?

There is a fast-food restaurant (I kid you not) called "Burgertown USA".

Where are you planning to visit in the U.S.?  You can buy a hamburger almost anywhere.  It's the quality of the burger you need to know about, so you will get a good one.  In and Out Burgers are good in California; Whataburger is good in Texas; McDonald's is not the greatest, but it's everywhere.  Same for Wendy's and Burger King.  Do NOT order a non-meat (vegetarian) burger.  They are terrible and might make you ill. 

      burger.com

They are even sold at gas stations - the quality and freshness is the only discrepancy although I am certainly not stigmatizing the ones found at convenience stores by default. I was born and raised here and have been to 4 countries abroad and burgers don't strike me as an American cliche' even if they are. 

all over the country.

Do not go to these sites. They will steal your credit card information.

Anywhere you want

any fast food place

Just about anywhere. All restaurants and fast food places have them. Just try a few till you find one you love. Enjoy.

Try a chain called Five Guys. Best burgers I’ve ever had.