McDonald's and Burger King are giving away free burgers for National Cheeseburger DayLifestyleSep 17 at 9:30 AM – Sep 17 at 11:49 AM3 outletsUnited StatesQuartzMcDonald's and Burger King are giving away free burgers for National Cheeseburger Day Sep 17 at 9:30 AMNBC Chicago40 juicy deals for National Cheeseburger Day seen Sep 17 at 11:49 AMTimes UnionNational Cheeseburger Day deals: Where to get free, discounted burgers Friday seen Sep 17 at 9:45 AM