Dire Bare
Legend
While this book is official, keep in mind it isn't a game book or a "5E" book. It's a licensed book, from DK.Huh! I wonder if we’ll get population numbers in the upcoming FR campaign books. Previously with 5e, they’ve mostly shied away from any kind of demographics. This is something I’ve missed from previous editions.
And population numbers in D&D books have always been goofy.
But 2 million for a large renaissance-era city isn't actually unrealistic, even before the fantasy elements get applied. Part of Waterdeep's fantasy is "enormous city".