The Ponce de Leon Hotel in St. Augustine, Florida. Built in 1888. 540 guest rooms.

ONE TOILET

"the hotel originally had only one private bathroom?"

https://www.hotelnewsresource.com/article76499.html

"Each of the hotel's 240 guest rooms had a fireplace as well as a radiator—but not a private bathroom."

https://books.google.com/books?id=Y5hxDwAAQBAJ&pg=PT135#v=snippet&q=private&f=false

They immediately started building more bathrooms when the hotel opened, most likely because of the backlash. These people just lazily repurposed an old building and called it a hotel. They found this building, and they had no idea how to use it, like usual.