National Cheeseburger Day is Sunday Sept. 18 and Americans cannot wait to grab a FREE cheeseburger from select restaurants that decided to participate in the national day of fun and good fast food.

Go to select locations around the U.S. for a FREE cheeseburger. Some places will have cheeseburgers at discounted prices or will not participate at all, so make sure to ask before placing your order on Sunday.

BurgerFi fans can get a double cheeseburger with BurgerFi sauce for just $5.

Restaurants in Past National Cheeseburger Day

Last year, Black Tap: Craft Burgers & Beer, combined National Cheeseburger Day with National Milkshake Day in a 19-dollar-offer of the All-American Burger and Peanut Butter Chocolate Milkshake.

Other joints that participated in National Cheeseburger Day included The Bonnie, Boulton & Watt, The Grayson, Uncle Sam’s and more.

5 Things You Need to Know

5 – The Stats

A Technomic’s Burger Consumer Trend Report found that about 57 percent of Americans ate burgers more than once a week in 2015, slightly down from the 68 percent of consumers in the U.S. who ate the same amount of burgers in 2013.

4 – Some Places Participate, But not for FREE

While there will be a few places where you can grab a FREE cheeseburger on National Cheeseburger Day, there will be other locations who participate in a different way rather than not participating at all. Ruby Tuesday will give customers a FREE cheeseburger coupon when they purchase an adult meal on Sunday Sept. 18. They can only redeem the coupon if they sign up for Ruby Tuesday’s SoConnected email club.

3 – You Can Get More Than a Cheeseburger

At Angus Steakhouse, customers have the option to get a coupon for the Steakhouse Bacon Cheeseburger until Sept. 19. They can also get a Guacamole Burger or ditch the beefy sandwich all together, for a FREE lunch entree with a value of $8.99. That could be good news for vegans or vegetarians.

2 – You Can Get Your Burger in the Air

Unlike green eggs and ham that you can eat anywhere, free burgers will only be available at select locations, and in the air. Delta Airlines will serve Shake Shack burgers on select flights leaving from JFK to LAX on National Cheeseburger Day.

1 – There is Hope for Vegetarians

Hurricane Grill & Wings will offer discounted veggie burgers for just $5.99. You can also get a beef or turkey burger for the same price topped with cheese, lettuce, tomato, onion and pickles.