The answer to the question is ...
... in (the humbly named 'city' of) Avondale Estates, Georgia, located just east of the city of Atlanta, Georgia.
There, on Labor Day, 1955, the first Waffle House diner opened for business. The building is now, yes, a (working) museum.
I took this picture on 7 March 2017, because of sad news from a few days earlier ...
Joe Rogers Sr., the restaurateur who founded 24-hour diner chain Waffle House with his partner Tom Forkner, died on Friday [3 March 2017]. He was 97. As a young man, Rogers worked as a short-order cook and manager at the now-defunct Toddle House chain. He opened the first Waffle House with his neighbor Forkner in Avondale Estates, Georgia, in 1955. Rogers and Forkner decided to call it Waffle House because waffles were the most profitable items on the menu. The duo expanded slowly, opening just a few more locations during the restaurant’s first decade in business. But growth accelerated in the ’70s and ’80s and now the chain has more than 1,900 outposts, most of which are located in the South. Even though he was the co-founder, Rogers liked to hop behind the counter from time to time. In 2004, the restaurateur told the Atlanta Journal-Constitution: “I’m not an executive, I’m a waffle cook.” Rogers pulled himself out of day-to-day operations of the chain decades ago, but he was still active at the company’s headquarters into his mid-80s.
Here are two more images from the session:
"Good Food Fast"... but tours (and waffles and smothered hash browns) by appointment only.