How big are the biggest cities in your campaign world?

[Yora]

I would guess that the largest city states in my setting might have some 100,000 people within the city itself. But that's really the exception.

 

[Lanefan]

Troll meat. Every family keeps a troll, and just carves off what they need.

And every 50 years or so thousands of Dwarves die in the latest Troll Uprising...

 

[Hand of Evil]

Can I raise a practical question at this point?

What do those 7.8 million Dwarves do for food?

Hydroponic and light spells, Guinea pigs and cave spiders (taste like crab when boiled), mushrooms and the race that looks like mushrooms (it is not cannibalism when it is a plant.)